1st year Chemistry

How to Prepare for MDCAT from Remote Areas Tips & Resources

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MDCAT preparation from remote/villages

Learn how to prepare for the MDCAT exam while living in remote/villages areas of Pakistan. Discover online resources, study plans, mock tests, and proven strategies to excel in your medical entrance test.

Preparing for the MDCAT (Medical and Dental College Admission Test) while living far from big cities is entirely possible with the right strategies and resources. Here’s a comprehensive guide to help you excel:

1. Develop a Study Plan

  • Set a Routine: Create a daily timetable that allocates specific hours for each subject (Biology, Chemistry, Physics, and English).
  • Prioritize Topics: Focus on high-weightage topics. Review the MDCAT syllabus provided by PMC (Pakistan Medical Commission).
  • Set Goals: Break down your syllabus into smaller tasks and set weekly targets.

2. Use Online Resources

  • Online Lectures: Platforms like YouTube, KIPS LMS, Step Learning, Edkasa, and Ilm Ki Dunya offer free or paid video lectures specifically for MDCAT preparation.
  • Practice Tests: Take advantage of websites offering mock tests and past papers, such as MDCAT Guide or Tabir Academy.
  • PMC Practice Portal: Access the PMC website for official mock tests and updates.

3. Invest in Quality Study Material

  • Books: Purchase recommended books like:
    • Punjab Textbook Board (PTB) books for Biology, Chemistry, and Physics.
    • National Curriculum-based MDCAT preparation books (e.g., Caravan or Dogar Publishers).
  • Notes: Obtain notes from reputable academies or students who have previously prepared for MDCAT.

4. Practice Regularly

  • Past Papers: Solve past MDCAT papers to familiarize yourself with the exam pattern.
  • Daily MCQs: Practice at least 100-150 MCQs daily from various subjects.
  • Error Analysis: Review your mistakes and revise those concepts.

5. Create a Conducive Study Environment

  • Distraction-Free Zone: Dedicate a quiet and comfortable space for studying.
  • Time Management: Study in focused blocks of 45-50 minutes followed by short breaks.

6. Seek Virtual Guidance

  • Online Tutors: Hire a tutor through platforms like TeacherOn or Preps.pk for personalized coaching.
  • Peer Groups: Join WhatsApp, Facebook, or Telegram groups where students share resources, discuss problems, and motivate each other.

7. Utilize Offline Resources

  • Local Libraries: Visit nearby libraries for access to books and a focused study environment.
  • Study Groups: Collaborate with fellow MDCAT aspirants in your area.

8. Focus on Health and Well-Being

  • Sleep: Ensure 7-8 hours of quality sleep daily.
  • Diet: Maintain a balanced diet to stay energized.
  • Exercise: Include physical activity in your routine to reduce stress.

9. Manage Internet and Power Limitations

  • If the internet is unreliable:
    • Download offline video lectures and MCQ apps (e.g., Topgrade).
    • Use hard copies of study materials.
  • For power outages, keep a backup of notes on mobile devices or printed formats.

10. Stay Updated

  • Regularly visit the official PMC website and social media channels for announcements and changes in the MDCAT syllabus or format.

11. Self-Motivation and Consistency

  • Set Rewards: Reward yourself for completing study milestones.
  • Stay Positive: Surround yourself with motivating individuals and maintain a positive outlook.

Final Thoughts:

With dedication, discipline, and the use of online and offline resources, you can effectively prepare for the MDCAT exam even in remote areas. Focus on smart strategies and remain consistent. Good luck!

Chapter 9 Acids and Bases – Solved Exercise for Federal Board Students

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Explore solved exercises of Chapter 9 Acids-Bases Chemistry. Includes explanations of ionization, hydrolysis, buffer solutions, and acid-base reactions for college-level learners.

2. Give Short Answers

(i) What are conjugate acid-base pairs? Explain with examples.
A conjugate acid-base pair consists of two species that differ by a single proton (H⁺). The acid donates a proton to become its conjugate base, while the base accepts a proton to form its conjugate acid.
Example:

  • HCl (acid) and Cl⁻ (conjugate base)
  • NH₃ (base) and NH₄⁺ (conjugate acid)

(ii) Define Lewis acid and Lewis base. Give one example of each.

  • Lewis Acid: A substance that can accept a pair of electrons.
    Example: AlCl₃
  • Lewis Base: A substance that can donate a pair of electrons.
    Example: NH₃

(iii) Write briefly about the ionization of water.
Water ionizes slightly to produce hydrogen ions (H⁺) and hydroxide ions (OH⁻):
H2O⇌H++OH−H₂O ⇌ H⁺ + OH⁻
The ionization constant of water at 25°C is Kw=[H+][OH−]=1.0×10−14Kw = [H⁺][OH⁻] = 1.0×10-14.

(iv) Define pH and pOH. Write the values of pH for acidic, basic, and neutral solutions.

  • pH: A measure of hydrogen ion concentration:
    pH=−log⁡[H+]
  • pOH: A measure of hydroxide ion concentration:
    pOH=−log⁡[OH−]
    Values:
  • Acidic: pH<7
  • Neutral: pH=7
  • Basic: pH>7

(v) What are Ka and pKa?

  • Ka: The acid dissociation constant, representing the strength of an acid.
  • pKa: The negative logarithm of Ka
    pKa=−log⁡(Ka)
    A lower pKa indicates a stronger acid.

(vi) What is the relationship between Ka and Kb?
The product of Ka (acid dissociation constant) and Kb (base dissociation constant) of a conjugate acid-base pair is equal to the ionization constant of water (Kw):
Ka⋅Kb=Kw=1.0×10−14

(vii) Give two examples of a buffer solution.

  1. Acetic acid and sodium acetate solution
  2. Ammonium chloride and ammonia solution

(viii) How does temperature impact solubility?
The solubility of most solids increases with temperature, while the solubility of gases decreases as temperature rises.

3. Elaborate on the ionization equation of water. How does it lead to the ion-product constant of water?

Water undergoes self-ionization, producing equal concentrations of H⁺ and OH⁻ ions:
H2O+H2O⇌H3O++OH−H₂O + H₂O ⇌ H₃O⁺ + OH⁻
At 25°C, the concentrations of H⁺ and OH⁻ are both 1.0×10-7, and the ion-product constant (Kw) is:
Kw=[H+][OH−]=1.0×10−14
This constant is essential for calculating pH and pOH in aqueous solutions.

4. What are buffer solutions? Elaborate with examples. Explain their significance in acid-base reactions.

Buffer solutions resist changes in pH when small amounts of acid or base are added.

  • Example 1: Acetic acid and sodium acetate buffer
  • Example 2: Ammonium hydroxide and ammonium chloride buffer
    Significance: Buffers maintain stable pH in biological systems, industrial processes, and chemical experiments.

5. Write detailed notes on each of the following:

(i) Conjugate acid-base pairs:
These pairs consist of an acid and its conjugate base or a base and its conjugate acid, differing by one proton. Examples include:

  • HCl and Cl⁻
  • NH₃ and NH₄⁺

(ii) pH:
pH is the measure of acidity or basicity of a solution, ranging from 0 to 14. It is calculated as:
pH=−log⁡[H+]

6. What is hydrolysis? Discuss the behavior of the following salts in aqueous solutions:

(i) K2SO4: This is a neutral salt, as neither K⁺ nor SO42- hydrolyzes in water.

(ii) NH4ClNH_4Cl: This salt is acidic in water because NH4+ hydrolyzes to produce H⁺:
NH4++H2O⇌NH3+H3O+

(iii) NaNO3: This is a neutral salt, as neither Na⁺ nor NO3− hydrolyzes in water.

Chapter 11: Nitrogen and Sulfur – Solved Exercise for Federal Board Islamabad

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Nitrogen and sulphur

Find detailed solutions to Chapter 11: Nitrogen and Sulfur exercises for Federal Board Islamabad students. Includes Haber process, ammonia production, sulfur properties, and more!

Chapter 11: Nitrogen and Sulfur

1. Ammonia Production and the Haber Process

(a) Hydrogen Production:
Hydrogen is produced by reacting methane with steam in the presence of a catalyst, yielding hydrogen and carbon monoxide.

(b) Reaction Equation for the Haber Process:
N2(g)+3H2(g)⇌k=350−450∘C,200atmIronCatalyst2NH3(g)N_2 (g) + 3H_2 (g) \xrightleftharpoons[k=350-450^\circ C, 200 atm]{Iron Catalyst} 2NH_3 (g)

(c) Conditions Necessary for Efficient Working of Haber Process:

  • Temperature: 400–450°C
  • Pressure: 200 atm
  • Catalyst: Finely divided iron with promoters like K₂O and Al₂O₃

2. Composition of Exhaust Gases

(a) CO₂ Contribution:
Carbon dioxide (CO₂) contributes to about 10% of the exhaust gas composition.

(b) Water Vapor in Exhaust Gas:
Water vapor is omitted from the exhaust composition as it condenses upon cooling.

(c) Significance of Nitrogen in Exhaust Gas:
Nitrogen is unreacted air that passes through the engine without reacting.

3. Ammonium Hydroxide and Ammonium Salts

(a) Ammonium Hydroxide:
Ammonium hydroxide is a weak base used in household cleaners.

(b) Ammonium Salts:
These salts are used as fertilizers due to their high nitrogen content.

4. Safety of Ammonia Use

Ammonia is highly hazardous as it is toxic, corrosive, and can irritate skin and respiratory tracts. Proper safety measures are necessary for its handling.

Chapter 12: Sulfur

5. Properties and Uses of Sulfur and Its Compounds

(a) Sulfur and Organic Products:
Sulfur is used in manufacturing rubber, fertilizers, and sulfuric acid.

(b) Sulfuric Acid Reactions:
(i) With Water: Produces heat due to exothermic reaction.
(ii) With Sugar: Causes dehydration to form carbon.

6. Reducing Agent Behavior of Sulfur

Sulfur dioxide acts as a reducing agent, especially in reactions with oxidizing agents like chlorine.

7. Environmental Concerns:

Sulfur emissions contribute to acid rain, harming ecosystems and infrastructure.

Chapter 12: Halogens – Comprehensive Exercise Solutions for Federal Board Students

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Halogens Solution

Access detailed solutions to Chapter 12: Halogens from Federal Board Chemistry syllabus. Includes multiple-choice answers, short questions, and comprehensive explanations on reactivity, oxidizing power, and trends of halogens. Perfect for college students!

Choose the Correct Answer

  1. Which halogen has a greenish-yellow color?
    Answer: (b) Cl₂
    Explanation: Chlorine (Cl₂) gas is greenish-yellow in color and is commonly used in water treatment and as a bleaching agent.
  2. Which halogen exists in a liquid state?
    Answer: (c) Br₂
    Explanation: Bromine (Br₂) is the only halogen that is a liquid at room temperature, and it has a reddish-brown color.
  3. Which of the following is the strongest reducing agent?
    Answer: (d) I⁻
    Explanation: Iodide ion (I⁻) is the strongest reducing agent among halides because it easily donates electrons compared to other halides.
  4. Oxidizing power of which halogen is highest?
    Answer: (a) F₂
    Explanation: Fluorine (F₂) is the most electronegative element and has the highest oxidizing power among halogens.
  5. Which is the strongest acid?
    Answer: (b) HCl
    Explanation: Hydrochloric acid (HCl) is a strong acid due to its complete dissociation in water, unlike HF, which forms hydrogen bonds and is weaker.

Give Short Answers

  1. Give the order of oxidizing power of halogens.
    Answer:
    The oxidizing power of halogens decreases down the group:
    F₂ > Cl₂ > Br₂ > I₂
    Fluorine is the strongest oxidizing agent because it has the highest electronegativity and smallest atomic size.
  2. How does the reactivity of halogens with hydrogen vary?
    Answer:
    The reactivity of halogens with hydrogen decreases down the group:
    F₂ > Cl₂ > Br₂ > I₂
    Fluorine reacts explosively with hydrogen, while iodine reacts slowly. This variation is due to the decreasing bond strength of hydrogen-halogen bonds down the group.
  3. Why is the strength of HF different from HCl?
    Answer:
    HF is a weaker acid compared to HCl because of the strong hydrogen bonding in HF, which reduces its ability to dissociate completely in water. In contrast, HCl dissociates fully, making it a stronger acid.
  4. Write reactions of sulfuric acid with NaCl and NaBr.
    Answer:
    • With NaCl:
      NaCl+H2SO4→HCl+NaHSO4NaCl + H₂SO₄ → HCl + NaHSO₄
      Produces hydrogen chloride gas.
    • With NaBr:
      NaBr+H2SO4→HBr+NaHSO4NaBr + H₂SO₄ → HBr + NaHSO₄
      Further oxidation occurs, producing bromine gas.
  5. What is a disproportionation reaction?
    Answer:
    A disproportionation reaction is a redox reaction in which the same element is simultaneously oxidized and reduced.
    Example: Chlorine in water:
    Cl2+H2O→HCl+HOClCl₂ + H₂O → HCl + HOCl
  1. Explain the reactions of chlorine with sodium hydroxide.
    Answer:
    Chlorine reacts with NaOH to form a disproportionation reaction:
    2NaOH+Cl2→NaCl+NaClO+H2O2NaOH + Cl₂ → NaCl + NaClO + H₂O
    This forms sodium chloride and sodium hypochlorite, commonly used in bleach.
  2. Describe the silver nitrate test for halide ions.
    Answer:
    • Add dilute nitric acid to remove carbonate or hydroxide impurities.
    • Add silver nitrate solution.
      • Chlorides (Cl⁻): White precipitate (AgCl)
      • Bromides (Br⁻): Cream precipitate (AgBr)
      • Iodides (I⁻): Yellow precipitate (AgI)
  3. How does sulfuric acid react with halide ions?
    Answer:
    Sulfuric acid reacts differently with halides:
    • Cl⁻: Produces HCl gas.
    • Br⁻: Produces Br₂ and SO₂ due to redox reactions.
    • I⁻: Produces I₂ and H₂S due to stronger reduction.
  4. Compare the strength of halogen acids.
    Answer:
    The strength of halogen acids increases as the bond strength decreases:
    HF < HCl < HBr < HI
    HI is the strongest because the bond dissociation energy is the lowest.
  5. Evaluate the reactivity of halogens.
    Answer:
    Reactivity decreases down the group:
    F₂ > Cl₂ > Br₂ > I₂
    Fluorine reacts most vigorously due to its high electronegativity and small atomic radius.
  6. Discuss trends in:
  • Volatility of halogens: Decreases down the group due to increasing molecular size and van der Waals forces.
  • Strength in halogen molecules: Bond strength decreases down the group due to increasing bond length.
  1. Interpret the reactivity of halogens as oxidizing agents.
    Answer:
    Halogens are strong oxidizing agents because they gain electrons easily. Reactivity decreases as electronegativity and reduction potential decrease down the group.

Chapter 13: Environmental Chemistry – Air Exercise

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Environmental Chemistry air

Explore detailed solutions to Chapter 13: Environmental Chemistry – Air for Federal Board students. Includes multiple-choice answers, short and long questions with explanations on air pollution, greenhouse gases, acid rain, ozone depletion, and measures to reduce pollution. Perfect for exam preparation and understanding environmental chemistry concepts.

Multiple Choice Questions

(i) What is a primary source of air pollution?

  • Answer: (a) Fossil fuel combustion.
    Explanation: Burning fossil fuels releases harmful gases like CO₂, SO₂, and NOx, which significantly contribute to air pollution.

(ii) Which gas is primarily responsible for the greenhouse effect?

  • Answer: (c) Carbon dioxide (CO₂).
    Explanation: CO₂ traps heat in the Earth’s atmosphere, leading to global warming and climate change.

(iii) Nitrogen oxide (NO₂) is NOT a greenhouse gas.

  • Answer: (b) Water vapor (H₂O).
    Explanation: While water vapor acts as a greenhouse gas, its effect is considered natural and not directly linked to human activities.

(iv) Which is a major component of smog that poses risks to humans?

  • Answer: (a) Sulfur dioxide (SO₂).
    Explanation: Sulfur dioxide combines with other particles to form harmful smog, impacting respiratory health.

(v) Acid rain is primarily caused by the emission of:

  • Answer: (c) Sulfur dioxide (SO₂).
    Explanation: SO₂ reacts with water vapor in the atmosphere to form sulfuric acid, which falls to the ground as acid rain.

Short-Answer Questions

1. What is the difference between global warming and climate change?

  • Global warming refers to the rise in Earth’s average temperature due to increased levels of greenhouse gases like CO₂ and CH₄.
  • Climate change encompasses global warming and includes long-term changes in weather patterns, sea levels, and ecosystems caused by these temperature shifts.

2. Describe the health effects of air pollution.

  • Air pollution causes respiratory diseases like asthma and bronchitis.
  • It increases the risk of cardiovascular problems, lung cancer, and strokes.
  • Particulate matter (PM2.5) and toxic gases like SO₂ and NO₂ impair lung function and reduce life expectancy.

3. What are the major greenhouse gases, and how do they affect the Earth?

  • Major Greenhouse Gases:
    • Carbon dioxide (CO₂)
    • Methane (CH₄)
    • Nitrous oxide (N₂O)
    • Chlorofluorocarbons (CFCs)
  • Effects:
    • Trap heat in the atmosphere, increasing global temperatures.
    • Lead to melting glaciers, rising sea levels, and extreme weather events.

4. Define acid rain and its environmental impacts.

  • Definition: Acid rain forms when sulfur dioxide (SO₂) and nitrogen oxides (NOx) react with water vapor to form acidic compounds, which fall to the ground as precipitation.
  • Impacts:
    • Damages forests and crops by altering soil pH.
    • Harms aquatic ecosystems by increasing water acidity, killing fish and plants.
    • Erodes buildings and monuments, especially those made of limestone or marble.

5. What are some measures to reduce air pollution?

  • Shift to renewable energy sources like solar and wind power.
  • Use public transportation and reduce the use of private vehicles.
  • Promote afforestation and protect existing forests.
  • Implement stricter regulations for industries to reduce emissions of pollutants like CO₂, NO₂, and SO₂.

Long-Answer Questions

6. Discuss the role of environmental chemistry in addressing air pollution.
Environmental chemistry helps us understand the composition of air and the reactions occurring within the atmosphere. By studying pollutants like CO₂, SO₂, and NO₂, scientists can develop technologies such as scrubbers and catalytic converters to minimize emissions. Research in this field aids in crafting policies for cleaner air and reducing human impact on climate change.

7. Evaluate the causes and effects of ozone layer depletion.

  • Causes:
    • Release of chlorofluorocarbons (CFCs) from aerosols, refrigerants, and solvents.
    • UV light breaks CFCs into chlorine atoms, which destroy ozone molecules.
  • Effects:
    • Increased UV radiation reaching Earth, leading to skin cancer and cataracts in humans.
    • Harmful effects on marine ecosystems, particularly plankton.
    • Reduced crop yields and damage to plants due to UV exposure.

8. Suggest steps to minimize the harmful effects of air pollution on health and the environment.

  • Regularly monitor air quality and avoid outdoor activities during high pollution levels.
  • Switch to energy-efficient appliances and vehicles.
  • Promote recycling and reduce waste incineration.
  • Create awareness campaigns to educate the public on the dangers of air pollution and methods to combat it.

Chapter 14 Environmental Chemistry-Water Exercise solution

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Environmental Chemistry-water

Looking for comprehensive solutions to the exercise questions of Chapter 14 Environmental Chemistry – Water for the Federal Board? This webpage provides detailed answers to all the exercise questions, including multiple-choice questions (MCQs), short-answer questions, and long-answer questions. Tailored specifically for college students under the Federal Board of Islamabad, our solutions cover key topics such as the distribution of water, water treatment methods, pollution impacts, and measures for water conservation.

Choose the Correct Answer

(ii) How much of the total water of the planet is present in the oceans?
Answer: (a) 90%
Explanation: About 90% of the Earth’s water is stored in oceans, making them the largest reservoir of water on the planet.

(iii) What type of pollutants can cause eutrophication?
Answer: (a) Agricultural
Explanation: Eutrophication is caused by agricultural pollutants, especially fertilizers rich in nitrates and phosphates, which promote excessive growth of algae in water bodies.

(iv) In which method are the small particles coagulated into big particles and then separated?
Answer: (b) Coagulation
Explanation: Coagulation involves adding substances like alum to water, causing small suspended particles to combine into larger clumps that can be easily removed by sedimentation or filtration.

(v) Which pollution can cause cancer?
Answer: (d) Heavy metals
Explanation: Pollutants like heavy metals (e.g., lead, mercury, cadmium) are toxic and carcinogenic, meaning they can cause cancer when ingested or absorbed by living organisms.

(vi) Disinfection of water is done by:
Answer: (d) All of the above
Explanation: Disinfection methods such as ozonation, UV radiation, and chlorination are widely used to kill microorganisms and make water safe for consumption.

(vii) World sources of freshwater are _ day by day.
Answer: (b) Decreasing
Explanation: Freshwater sources are depleting due to overuse, pollution, and climate change, posing a significant threat to global water security.

Descriptive Questions

2. Explain the distribution of water on the global level.
Water on Earth is unevenly distributed among different reservoirs:

  • Oceans: Hold about 90% of Earth’s water, mostly saline.
  • Glaciers and Ice Caps: Store approximately 2% of the total water, mainly as freshwater.
  • Groundwater: Makes up around 1% and is a significant source of freshwater.
  • Rivers, Lakes, and Streams: Constitute a very small fraction but are vital for human consumption and ecosystems.
  • Atmosphere: Contains a minimal amount in the form of water vapor.

3. How raw water treatment is done for municipal water supply?
Raw water treatment involves several stages:

  1. Screening: Removes large debris such as leaves and trash.
  2. Coagulation and Flocculation: Chemicals like alum are added to form clumps of dirt and particles.
  3. Sedimentation: Heavy particles settle at the bottom, leaving cleaner water at the top.
  4. Filtration: Water passes through sand and gravel to remove smaller particles.
  5. Disinfection: Chlorine, ozone, or UV light is used to kill harmful bacteria and viruses.

4. Why does water dissolve many substances, and why is it called a universal solvent?
Water is called the universal solvent because:

  • Polarity: Water molecules have a polar nature, allowing them to interact with various ions and polar compounds.
  • Hydrogen Bonding: It forms hydrogen bonds with solutes, breaking them apart into their components.
    This ability makes water vital for life, as it dissolves nutrients, gases, and waste products in biological systems.

5. Evaluate the strain on freshwater availability by agriculture and industry.

  • Agriculture: Accounts for about 70% of global freshwater use. Irrigation and crop production require massive amounts of water, often leading to over-extraction and depletion of aquifers.
  • Industry: Consumes significant water for manufacturing, cooling, and cleaning processes, polluting freshwater sources with chemicals and waste.
    These demands reduce freshwater availability for domestic and ecological purposes.

6. Suggest some measures to ensure the preservation of water reservoirs.

  • Efficient Irrigation: Use drip or sprinkler systems to reduce water wastage.
  • Pollution Control: Prevent industrial effluents and agricultural runoff from entering water bodies.
  • Rainwater Harvesting: Collect and store rainwater for future use.
  • Public Awareness: Educate people about the importance of conserving water.
  • Government Policies: Enforce strict regulations on water usage and pollution.

7. Evaluate the impact of pollutants on the ecosystem.
Pollutants like heavy metals, pesticides, and industrial waste harm ecosystems in the following ways:

  • Aquatic Life: Toxic substances cause diseases and death in fish and other aquatic organisms.
  • Eutrophication: Excess nutrients lead to algal blooms, depleting oxygen levels and killing aquatic species.
  • Bioaccumulation: Harmful chemicals accumulate in organisms, moving up the food chain and affecting humans.
  • Water Quality: Pollutants degrade water quality, making it unsafe for drinking and agriculture.

Chapter 15 Solved Exercise Organic Chemistry

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Organic Chemistry Federal board

Explore comprehensive chemistry resources for Federal Board students! This section covers essential topics like functional groups, alkyl groups, isomerism, reaction mechanisms, homologous series, and bond fissions. With detailed explanations, structural formulae, and solved exercises, students can deepen their understanding of organic chemistry concepts and prepare effectively for exams. Perfectly tailored for Federal Board college students, these resources simplify complex topics with clear examples and systematic solutions.

Detailed Solutions for College Students (Federal Board, Islamabad)

1. Importance of Functional Groups

Functional groups are specific groups of atoms within molecules responsible for their chemical properties and reactions. They determine the reactivity, solubility, and physical properties of a compound. For example:

  • Hydroxyl group (-OH): Present in alcohols, makes compounds polar and soluble in water.
  • Carbonyl group (-C=O): Present in ketones and aldehydes, critical in organic reactions like nucleophilic addition.

2. Alkyl Group

An alkyl group is a hydrocarbon fragment derived by removing one hydrogen atom from an alkane. Its general formula is ( C_nH_{2n+1} ).

Alkyl Groups from Isomers of Propane:

  1. Propyl (CH3CH2CH2)
  2. Isopropyl (CH3CHCH3)

Alkyl Groups from Isomers of Butane:

  1. Butyl CH3CH2CH2CH2-
  2. Isobutyl (CH3CH(CH3)CH3)
  3. Sec-butyl CH3CH(CH3)CH2-
  4. Tert-butyl C(CH3)3-

3. Systematic Names for Compounds

i. CH3CH2COCl: Propanoyl chloride
ii. CH3CN: Ethanenitrile
iii. CH3OCH3: Methoxymethane (Dimethyl ether)

4. Correction of Wrong Names

a. 1-methylpentane:

  • Correct structure: This name is invalid because a methyl group cannot be attached to the first carbon of pentane.
  • Correct name: Hexane

b. 2-ethylbutane:

  • Correct structure: This name is invalid because the longest chain would be pentane.
  • Correct name: 3-methylpentane

c. 2-methylcyclohexane:

  • Correct structure: Valid name.

d. 3,3-methyl-4-ethylheptane:

  • Correct structure: This name is invalid because substituents must be numbered with the lowest possible set of numbers.
  • Correct name: 3-ethyl-4,4-dimethylheptane

5. Electrophiles and Nucleophiles

  • Electrophile: Electron-deficient species that accepts electrons during a reaction. Examples: ( H+ ), ( NO2+ ).
  • Nucleophile: Electron-rich species that donates electrons during a reaction. Examples: ( OH– ), ( CN– ).

6. Chain Isomerism, Metamerism, and Positional Isomerism

  • Chain Isomerism: Compounds with the same molecular formula but different arrangements of the carbon chain.
    Example: n-butane and isobutane (C4H10).
  • Metamerism: Compounds with the same molecular formula but different alkyl groups on either side of a functional group.
    Example: ( CH3OCH2CH3 ) and ( CH3CH2OCH3 ).
  • Positional Isomerism: Compounds with the same molecular formula but different positions of a functional group.
    Example: ( CH3CH2OH ) and ( CH3OCH3 ).

7. Structural Isomers of C4H9Br

  1. 1-bromobutane
  2. 2-bromobutane
  3. 1-bromo-2-methylpropane
  4. 2-bromo-2-methylpropane

8. Aliphatic Compounds

Aliphatic compounds are organic compounds with straight or branched chains.
Examples: Methane (CH4), Ethane (C2H6).

9. Skeletal vs. 2D Displayed Structural Formulae

  • Skeletal Formula: Simplified representation showing only bonds between carbon atoms.
  • 2D Displayed Formula: Shows all bonds and atoms explicitly.

Examples:

  1. Methane: ( CH_4 )
  2. Ethanol: ( CH_3CH_2OH )

10. Molecular Formula of Compound

Given: Molecular mass = 26 amu, Empirical formula = CH.

  • Empirical mass = 12 (C) + 1 (H) = 13 amu.
  • Molecular formula = ( CH X 2 = C2H2 ).

11. Homologous Series

A homologous series is a group of organic compounds with the same functional group and similar chemical properties but differing by a CH2 unit.
Features:

  • Gradual change in physical properties.
  • Same general formula.
  • Similar chemical properties.

12. Free Radical Substitution Reaction

Definition: A reaction where a free radical replaces a hydrogen atom.
Example: Bromination of methane:

13. Nucleophilic Substitution and Electrophilic Addition

  • Nucleophilic Substitution: Replacement of a leaving group by a nucleophile. Example: Hydrolysis of alkyl halides.
  • Electrophilic Addition: Addition of an electrophile to a double or triple bond. Example: Bromination of ethene.

14. Structural Isomerism

  • Functional Group Isomerism: Compounds with the same molecular formula but different functional groups. Example: ( CH3OH ) and ( CH3OCH3 ).
  • Tautomerism: Dynamic equilibrium between structural isomers. Example: Keto-enol tautomerism.

15. Homolytic and Heterolytic Fission

Halogenation of Alkanes:
Homolytic fission produces free radicals, initiating the substitution of hydrogen atoms in alkanes with halogens.

Chapter 10 Periodic table Solved Exercise

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Periodic table solved Exercise

Master the fundamentals of periodic table trends and reactions with this detailed guide. Explore key concepts, including ionization energy, electron affinity, and metallic vs. non-metallic character. Learn how sodium and magnesium react with oxygen, chlorine, and water, and uncover the variations in the nature of oxides across Period 3. Understand the significance of atomic radii trends, the amphoteric behavior of Al2​O3​, and the classification of s- and p-block elements. Dive into practical examples and explanations to simplify your study of chemistry and ace your exams!

Multiple Choice Questions (MCQs)

(i) Correct answer: (d) principal quantum number
Explanation: The period number corresponds to the principal quantum number (( n )) of the outermost shell of electrons.

(ii) Correct answer: (a) F
Explanation: Fluorine has the highest electronegativity due to its small size and high effective nuclear charge.

(iii) Correct answer: (a) Na2O
Explanation: Na2O is a basic oxide and produces a base (NaOH) when dissolved in water.

(iv) Correct answer: (d) alkaline earth metal
Explanation: Magnesium (Mg) belongs to Group 2A (alkaline earth metals).

(v) Correct answer: (b) group 14
Explanation: The electron configuration (1s(^2), 2s(^2), 2p(^6), 3s(^2), 3p(^2)) corresponds to silicon (Si), which is in Group 14.

(vi) Correct answer: (a) Li
Explanation: Lithium has the highest ionization energy due to its smaller size compared to the other elements in the group.

(vii) Correct answer: (d) I
Explanation: Iodine has the lowest electron affinity due to its large atomic size and lower effective nuclear charge.

(viii) Correct answer: (c) Al(_2)O(_3)
Explanation: Aluminum oxide (Al2O3) is amphoteric as it reacts with both acids and bases.

(ix) Correct answer: (d) G-VIIA
Explanation: Elements in Group VIIA (halogens) have strong non-metallic character due to their high electronegativity.

(x) Correct answer: (a) B
Explanation: Boron has the smallest ionization energy among the given options because of its lower nuclear charge compared to other elements.

Short Answer Questions

(i) What is a period?
A period is a horizontal row in the periodic table. Elements in the same period have the same number of electron shells.

(ii) Differentiate between s-block and p-block elements.

  • s-block elements: These elements have their outermost electrons in the s-orbital (Groups 1 and 2).
  • p-block elements: These elements have their outermost electrons in the p-orbital (Groups 13 to 18).

(iii) Position of sulfur (atomic number 16) in the periodic table:

  • Electron configuration: 1s(^2), 2s(^2), 2p(^6), 3s(^2), 3p(^4).
  • Period: 3 (3 electron shells), Group: 16 (6 valence electrons).

(iv) Position of element with configuration 1s(^2), 2s(^2), 2p(^6), 3s(^2), 3p(^3):

  • Electron configuration corresponds to phosphorus (P).
  • Period: 3, Group: 15 (5 valence electrons).

(v) How do metals differ from metalloids?

  • Metals are good conductors of heat and electricity, malleable, ductile, and have metallic luster.
  • Metalloids have properties intermediate between metals and non-metals (e.g., semiconductors like silicon).

(vi) Why is a cation smaller than its atom?
A cation forms when an atom loses one or more electrons, resulting in decreased electron-electron repulsion and a stronger attraction of the remaining electrons toward the nucleus.

Descriptive Questions

1. Describe the reactions of sodium and magnesium with:
(i) Oxygen:

  • Sodium reacts to form sodium oxide (Na2O).
  • Magnesium reacts to form magnesium oxide (MgO).

(ii) Chlorine:

  • Sodium forms sodium chloride (NaCl).
  • Magnesium forms magnesium chloride (MgCl2).

(iii) Water:

  • Sodium reacts vigorously with water to form sodium hydroxide (NaOH) and hydrogen gas.
  • Magnesium reacts slowly with water at room temperature but more rapidly with steam to form MgO and hydrogen gas.

2. Variation in nature of oxides of Period 3 elements:

  • Oxides vary from basic (e.g., Na2O) to amphoteric (e.g., Al2O3) to acidic (e.g., SO3).

3. Variation in metallic and non-metallic character in the periodic table:

  • Metallic character increases down a group and decreases across a period.
  • Non-metallic character decreases down a group and increases across a period.

4. Why do atomic radii decrease across a period?
As you move across a period, the number of protons increases, resulting in a greater nuclear charge, which pulls electrons closer to the nucleus.

5. Why do atomic radii increase down a group?
As you move down a group, additional electron shells are added, increasing the distance between the nucleus and the outermost electrons.

6. How does the periodic table help in understanding the properties of elements?
The periodic table organizes elements based on their atomic structure, allowing predictions of their chemical and physical properties (e.g., reactivity, electronegativity, and ionization energy).

7. Significance of the periodic table:

  • Systematic classification of elements.
  • Predicts element properties and trends.
  • Helps in understanding the chemical behavior and bonding of elements.

8. Periodic table and oxide characteristics across periods:

  • Moving left to right, oxides change from basic (Na2O, MgO) to amphoteric (Al2O3) to acidic (SO3), P2O5).

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Strategies

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Physics MCQs

  1. Which one is the highest power multiple?
  • (A) Giga
  • (B) Mega
  • (C) Tera
  • (D) Deca
    Answer: (C) Tera
  1. SI unit of charge is:
  • (A) Ampere
  • (B) Coulomb
  • (C) Volt
  • (D) Calorie
    Answer: (B) Coulomb
  1. The electrical analog of mass in electricity is:
  • (A) Capacitance
  • (B) Charge
  • (C) Inductance
  • (D) Resistance
    Answer: (C) Inductance
  1. Which one of the following relations is correct?
  • (A) 1 wb m⁻² = N m⁻¹ A⁻¹
  • (B) 1 wb m⁻² = 1 Tesla
  • (C) 1 Tesla = 10⁴ Gausses
  • (D) All of these
    Answer: (D) All of these
  1. Lifetime of an electron in a metastable state is about:
  • (A) 10⁻⁵ sec
  • (B) 10⁻⁸ sec
  • (C) 10⁻³ sec
  • (D) 10⁻² sec
    Answer: (A) 10⁻⁵ sec
  1. The torque acting on a current-carrying coil is given by:
  • (A) τ = NIAB cos α
  • (B) τ = NIAB sin α
  • (C) τ = BIL sin α
  • (D) τ = BIL cos α
    Answer: (B) τ = NIAB sin α
  1. The grid in the cathode ray oscilloscope:
  • (A) Controls the number of waves
  • (B) Accelerates electrons
  • (C) Controls the brightness of the spot formed
  • (D) Has positive potential with respect to the cathode
    Answer: (C) Controls the brightness of the spot formed
  1. The horizontal range of a projectile, at a certain place, is completely determined by:
  • (A) The angle of projection
  • (B) The mass of the projectile
  • (C) The initial velocity of projection
  • (D) Speed and mass of the projectile
    Answer: (C) The initial velocity of projection
  1. If velocity is doubled, then:
  • (A) Momentum increases 4 times, and K.E. increases 2 times
  • (B) Momentum and K.E. remain the same
  • (C) Momentum increases 2 times, and K.E. increases constantly
  • (D) Momentum increases 2 times, and K.E. increases 4 times
    Answer: (D) Momentum increases 2 times, and K.E. increases 4 times
  1. The consumption of energy by a 60-watt bulb in 2 seconds is:
    • (A) 20 J
    • (B) 30 J
    • (C) 120 J
    • (D) 0.02 J
      Answer: (C) 120 J
  2. In transistors, the base region is very thin, of the order of:
    • (A) 10⁻⁵ cm
    • (B) 10⁻⁶ mm
    • (C) 10⁻⁶ m
    • (D) 10⁻⁶ µm
      Answer: (A) 10⁻⁵ cm
  3. The closed-loop gain of an OP-AMP depends on:
    • (A) Internal structure of the OP-AMP
    • (B) Voltage of power supplies
    • (C) Externally connected resistances
    • (D) Input resistance
      Answer: (C) Externally connected resistances
  4. The net charge on an N-type substance is:
    • (A) 0.7 volts
    • (B) 0.25 volts
    • (C) 0.3 volts
    • (D) 0.07 volts
      Answer: (A) 0.7 volts
  5. The value of Wien’s constant is:
    • (A) 2.90 × 10⁻³ mK
    • (B) 4.22 × 10⁻⁷ mK
    • (C) 3.34 × 10⁻⁴ mK
    • (D) 3.42 × 10⁻⁸ mK
      Answer: (A) 2.90 × 10⁻³ mK
  6. The minimum frequency below which no electron is emitted from the metal surface is called:
    • (A) High frequency
    • (B) Threshold frequency
    • (C) Low frequency
    • (D) Resonance frequency
      Answer: (B) Threshold frequency
  7. In pair production, the type of photon used is:
    • (A) α-particle
    • (B) X-rays
    • (C) β-particle
    • (D) γ-radiations
      Answer: (D) γ-radiations
  8. The lifetime of an electron in an excited state is about 10⁻⁸ s. What is its uncertainty in energy during this time?
    • (A) 1.05 × 10⁻⁴¹ J
    • (B) 1.15 × 10¹⁰ J
    • (C) 1.05 × 10⁻²⁶ J
    • (D) 2.19 × 10⁻⁴⁰ J
      Answer: (C) 1.05 × 10⁻²⁶ J
  9. Velocity of an electron moving in the first orbit of hydrogen is:
    • (A) 2.19 × 10⁷ m/s
    • (B) 2.2 × 10⁸ m/s
    • (C) 2.18 × 10⁷ m/s
    • (D) 2.19 × 10⁶ m/s
      Answer: (A) 2.19 × 10⁷ m/s
  10. LASER is a potential energy source for inducing which type of reaction?
    • (A) Radioactive
    • (B) Ionization
    • (C) Fission
    • (D) Fusion
      Answer: (D) Fusion
  11. In the half-life of an element, the equation for the number of decaying atoms is given by:
    • (A) ΔN ∝ -NΔt
    • (B) ΔN ∝ -nΔt
    • (C) ΔN = KNΔt
    • (D) ΔN = -ΔNΔt
      Answer: (A) ΔN ∝ -NΔt
  12. Decay constant ‘λ’ is given as:
    • (A) -ΔN/Δt
    • (B) Δt/ΔN
    • (C) ΔN/NΔt
    • (D) -ΔN/NΔt
      Answer: (D) -ΔN/NΔt
  13. The SI unit of absorbed dose ‘D’ i.e., radiation effect, is Gray, and one Gray is equal to:
    • (A) kJ/mol
    • (B) kg/J
    • (C) J/mol
    • (D) J/kg
      Answer: (D) J/kg
  14. The principle of homogeneity of dimensions determines:
    • (A) Only variable in the equation
    • (B) Correctness of an equation
    • (C) Only constant in the equation
    • (D) Constant and variable in the equation
      Answer: (B) Correctness of an equation
  15. For a body to be in complete equilibrium:
    • (A) Linear acceleration is zero
    • (B) Angular acceleration is zero
    • (C) Linear acceleration is zero, but angular acceleration is not zero
    • (D) Linear acceleration and angular acceleration both should be zero
      Answer: (D) Linear acceleration and angular acceleration both should be zero
  16. If the length of a spanner is ‘l’ and a force ‘F’ is applied on it to tighten a nut such that it passes through the pivot point, then torque is:
    • (A) Zero
    • (B) F*l sin θ
    • (C) F*f
    • (D) Fl sin θλ Answer: (B) Fl sin θ
  17. **If a force of magnitude 8 N acts on a body in a direction making an angle of 30°, its x and y components will be:**
    • (A) Fx = 4√3 and Fy = 8
    • (B) Fx = 4√3 and Fy = 4
    • (C) Fx = 8 and Fy = 4√3
    • (D) Fx = 8√3 and Fy = 4
      Answer: (B) Fx = 4√3 and Fy = 4
  18. The difference of a vector ¯B and its negative vector -B is:
    • (A) A null vector
    • (B) Twice the magnitude of vector ¯B¯
    • (C) Equal to the magnitude of vector ¯B¯
    • (D) Smaller than the magnitude of vector ¯B¯
      Answer: (B) Twice the magnitude of vector ¯B¯
  19. Time of projectile’s flight is:
    • (A) vi² sin² θ/g
    • (B) vi² sin θ /g
    • (C) 2 vi sin θ/g
    • (D) vi sin 2θ/g
      Answer: (C) 2 vi sin θ/g
  20. If the velocity of the body changes by equal amounts in equal intervals of time, the body is said to have:
    • (A) Variable acceleration
    • (B) Uniform velocity
    • (C) Uniform acceleration
    • (D) Negative acceleration
      Answer: (C) Uniform acceleration
  21. In order to determine the maximum height of the projectile, the equation of motion used is:
    • (A) aS = v² – v₀²
    • (B) 2S = a(v² – v₀²)
    • (C) 2aS = v² – v₀²
    • (D) aS = 2(v² – v₀²)
      Answer: (C) 2aS = v² – v₀²

  1. If a force of 12 N acts on a car and changes its momentum from 36 kg·m/s to 60 kg·m/s, the time during which this change occurs will be:
  • (A) 24 sec
  • (B) 12 sec
  • (C) 2 sec
  • (D) 8 sec
    Answer: (C) 2 sec
  1. Which one of the following is a non-conservative force?
  • (A) Electric force
  • (B) Gravitational force
  • (C) Elastic spring force
  • (D) Frictional force
    Answer: (D) Frictional force
  1. Value of escape velocity for the surface of the earth is 11 km/s. Its value for the surface of the moon is:
  • (A) 11 km/s
  • (B) 2.4 km/s
  • (C) 10.4 km/s
  • (D) 4.3 km/s
    Answer: (B) 2.4 km/s
  1. On a clear day at noon, the intensity of solar energy reaching the earth’s surface is about:
  • (A) 1.0 kW·m⁻²
  • (B) 1.0 W·m⁻²
  • (C) 1.4 kW·m⁻²
  • (D) 1.4 W·m⁻²
    Answer: (C) 1.4 kW·m⁻²
  1. When a lift is accelerated upward, the apparent weight of an object in it will be:
  • (A) Equal to its real weight
  • (B) Zero
  • (C) Less than its real weight
  • (D) Greater than its real weight
    Answer: (D) Greater than its real weight
  1. The moment of inertia of a thin rod is:
  • (A) 1/2 ML2
  • (B) ( mL^2 )
  • (C) ( \frac{1}{12} mL^2 )
  • (D) ( \frac{1}{4} mL^2 )
    Answer: (C) ( \frac{1}{12} mL^2 )
  1. A wheel of radius 1 m covers an angular displacement of 180°. Its linear displacement is:
  • (A) 3.14 m
  • (B) 6.28 m
  • (C) π rad
  • (D) 0.157 m
    Answer: (A) 3.14 m
  1. Conservation of mass of fluid flow leads to:
  • (A) Bernoulli’s equation
  • (B) Equation of motion
  • (C) Venturi meter
  • (D) Equation of continuity
    Answer: (D) Equation of continuity
  1. The blood vessels collapse when:
  • (A) External pressure applied becomes greater than the systolic pressure
  • (B) External pressure applied is equal to the systolic pressure
  • (C) External pressure applied is less than the systolic pressure
  • (D) External pressure applied is zero
    Answer: (A) External pressure applied becomes greater than the systolic pressure
  1. An oscillating body is at the mean position at ( t = 0 ). At ( t = T/4 ), it will be at:
  • (A) Extreme position
  • (B) Between extreme and mean position
  • (C) Mean position
  • (D) Beyond extreme position
    Answer: (A) Extreme position
  1. In a simple pendulum, the tension of the string is:
  • (A) ( g \cos \theta )
  • (B) ( mg \cos \theta )
  • (C) ( mg \sin \theta )
  • (D) ( mg )
    Answer: (B) ( mg \cos \theta )
  1. Two sound waves having the same amplitudes are moving in the same direction and are out of phase. The amplitude of the resultant wave is:
  • (A) Zero amplitude
  • (B) Difference of the amplitudes of the two waves
  • (C) The sum of amplitudes of the two waves
  • (D) Double the amplitude of either wave
    Answer: (B) Difference of the amplitudes of the two waves
  1. A source ‘Y’ of unknown frequency produces 4 beats with a source of 240 Hz and 8 beats with a source of 252 Hz. Frequency of the source ‘Y’ is:
  • (A) 244 Hz
  • (B) 248 Hz
  • (C) 236 Hz
  • (D) 246 Hz
    Answer: (D) 246 Hz
  1. An organ pipe closed at one end has a length of 25 cm. Wavelength of the fundamental note is:
  • (A) 25 cm
  • (B) 100 cm
  • (C) 50 cm
  • (D) 75 cm
    Answer: (B) 100 cm
  1. In the Newton ring apparatus, at the point of contact of the lens and glass plate, the additional path difference introduced is:
  • (A) λ/4
  • (B) λ
  • (C) λ/2
  • (D) λ/3
    Answer: (C) ( λ/2 )
  1. The path difference ‘BD’ for destructive interference is:
  • (A) ( (m + \frac{1}{2}) \lambda )
  • (B) ( d \sin \theta )
  • (C) ( m \lambda )
  • (D) ( 3 \lambda )
    Answer: (A) ( (m + \frac{1}{2}) \lambda )
  1. In the case of a grating spectrometer, the resolving power ‘R’ of the grating is defined as:
  • (A) λ/ Delta λ
  • (B) λ /λ1
  • (C) λ / D
  • (D) N x m
    Answer: (A)
  1. Which one of the following lights travels fastest in optical fibers?
  • (A) Visible light
  • (B) Ordinary light
  • (C) Ultraviolet light
  • (D) Invisible infrared light
    Answer: (D) Invisible infrared light
  1. The value of the universal gas constant is:
  • (A) ( 8.314 \, \text{J·mol⁻¹·K⁻¹} )
  • (B) ( 7.23 \, \text{J·mol⁻¹·K⁻¹} )
  • (C) ( 8.324 \, \text{J·mol⁻¹·K⁻¹} )
  • (D) ( 1.00 \, \text{J·mol⁻¹·K⁻¹} )
    Answer: (A) ( 8.314 \, \text{J·mol⁻¹·K⁻¹} )
  1. The turbine in a steam power plant takes steam from a boiler at 427°C and exhausts into a low-temperature reservoir at 77°C. What is the maximum possible efficiency?
  • (A) 50%
  • (B) 60%
  • (C) 40%
  • (D) 70%
    Answer: (B) 60%
  1. Which one of the following is a postulate of the kinetic theory of gases?
  • (A) Molecules do not exert force on each other
  • (B) The size of molecules is much larger than the separation between the molecules
  • (C) A finite volume of gas consists of very few molecules
  • (D) Gas molecules are not in random motion
    Answer: (A) Molecules do not exert force on each other
  1. Which one is not an irreversible process?
  • (A) Slow compression of a gas into a cylinder
  • (B) Explosion
  • (C) Changes due to friction
  • (D) Dissipation of energy
    Answer: (A) Slow compression of a gas into a cylinder
  1. Electric intensity is a vector quantity and its direction is:
  • (A) Perpendicular to the direction of the field
  • (B) At a certain angle
  • (C) Opposite to the direction of force
  • (D) Along the direction of force
    Answer: (D) Along the direction of force
  1. The magnitude of an electric field between two separated plates can be calculated by the relation:
  • (A) ( \Delta V = Ed )
  • (B) ( \Delta V = E/d )
  • (C) ( \Delta V = E \cdot d )
  • (D) ( E = \Delta V \cdot d )
    Answer: (A) ( \Delta V = Ed )
  1. SI unit of electric flux is:
  • (A) Nm·C⁻¹
  • (B) Nm²·C⁻²
  • (C) Nm⁻²·C⁻²
  • (D) Nm²·C⁻¹
    Answer: (D) Nm²·C⁻¹
  1. The equivalent current that passes from a higher potential to a lower potential point, as if it represented a movement of positive charges, is:
  • (A) Electronic current
  • (B) Magnetic lines
  • (C) Electric current
  • (D) Conventional current
    Answer: (D) Conventional current
  1. If ‘V’ is the applied potential difference across a resistance ‘R’, the loss in potential energy per unit time is:
  • (A) ( VI )
  • (B) ( \frac{V^2}{R} )
  • (C) ( I^2R )
  • (D) All of the above
    Answer: (D) All of the above
  1. The substances like germanium and silicon have:
  • (A) Negative temperature coefficients
  • (B) Both A and B
  • (C) Positive temperature coefficients
  • (D) None of the above
    Answer: (A) Negative temperature coefficients
  1. The sensitivity of a galvanometer can be decreased by:
  • (A) Increasing the magnetic field
  • (B) Increasing BAN ratio
  • (C) Increasing the number of turns of the coil
  • (D) Decreasing the length of couple ‘c’
    Answer: (A) Increasing the magnetic field
  1. Force on a current-carrying conductor in a uniform magnetic field is:
  • (A) ( F = NIA \cos \alpha )
  • (B) ( F = ILB \sin \alpha )
  • (C) ( F = \mu nI )
  • (D) ( F = ILA \cos \alpha )
    Answer: (B) ( F = ILB \sin \alpha )

Chemistry

  1. In an electrochemical series, standard electrode potentials are arranged on the basis of:
  • (A) pH scale
  • (B) Hydrogen scale
  • (C) pOH scale
  • (D) pKa scale
    Answer: (B) Hydrogen scale
  1. The reaction responsible for the production of electricity in a Voltaic cell is:
  • (A) Hydrolysis reaction
  • (B) Redox reaction
  • (C) Oxidation reaction
  • (D) Reduction reaction
    Answer: (B) Redox reaction
  1. Glucose is converted into ethanol by the enzyme present in yeast:
  • (A) Urease
  • (B) Sucrase
  • (C) Invertase
  • (D) Zymase
    Answer: (D) Zymase
  1. The rate of reaction involving ions can be studied by the method:
  • (A) Dilatometric
  • (B) Optical rotation
  • (C) Refractometric
  • (D) Electrical conductivity
    Answer: (D) Electrical conductivity
  1. When one mole of gaseous hydrogen ions are dissolved in water to form an infinitely dilute solution, the amount of heat liberated is:
  • (A) -1891 kJ/mol
  • (B) -499 kJ/mol
  • (C) -1075 kJ/mol
  • (D) -1562 kJ/mol
    Answer: (C) -1075 kJ/mol
  1. Energy required to remove an electron from the outermost shell of its isolated gaseous atom in the ground state is called:
  • (A) Electron affinity
  • (B) Ionization energy
  • (C) Lattice energy
  • (D) Crystal energy
    Answer: (B) Ionization energy
  1. Which of the following carbonates of alkali metals is not stable toward heat and is decomposed on heating to its oxide along with liberation of CO₂?
  • (A) Li₂CO₃
  • (B) K₂CO₃
  • (C) Mg₂CO₃
  • (D) Na₂CO₃
    Answer: (A) Li₂CO₃
  1. The presence of calcium is essential for the normal development of plants. An adequate supply of calcium appears to stimulate the development of which part of the plants?
  • (A) Leaves
  • (B) Root hairs
  • (C) Fruits
  • (D) Branches
    Answer: (B) Root hairs
  1. Which of the following sulfates is not soluble in water?
  • (A) Sodium sulfate
  • (B) Potassium sulfate
  • (C) Barium sulfate
  • (D) Zinc sulfate
    Answer: (C) Barium sulfate
  1. The trend in the densities of elements of Group III-A of the periodic table is:
  • (A) A gradual increase
  • (B) First decrease, then increase
  • (C) A gradual decrease
  • (D) First increase, then decrease
    Answer: (B) First decrease, then increase
  1. White lead has one of the following properties:
  • (A) Acidic
  • (B) Amorphous
  • (C) Crystalline
  • (D) Neutral
    Answer: (C) Crystalline
  1. The strongest acid among the following is:
  • (A) HF
  • (B) HCl
  • (C) HI
  • (D) HBr
    Answer: (C) HI
  1. The noble gas used in radiotherapy of cancer is:
  • (A) Radon
  • (B) Krypton
  • (C) Xenon
  • (D) Argon
    Answer: (A) Radon
  1. Paramagnetic behavior of an atom, ion, or molecule is due to the presence of:
  • (A) Unpaired electrons
  • (B) Protons
  • (C) Paired electrons
  • (D) Neutrons
    Answer: (A) Unpaired electrons
  1. The geometry of complexes depends upon the type of _ taking place in the valence shell of the central metal atom:
  • (A) Hybridization
  • (B) Deprotonation
  • (C) Protonation
  • (D) Dissociation
    Answer: (A) Hybridization
  1. KMnO₄ acts as a:
  • (A) Reducing agent
  • (B) Germicide
  • (C) Excellent precipitating reagent
  • (D) Oxidizing agent
    Answer: (D) Oxidizing agent
  1. Gasoline of higher octane number can be obtained by:
  • (A) Oxidative cleavage
  • (B) Catalytic cracking
  • (C) Thermal cracking
  • (D) Steam cracking
    Answer: (B) Catalytic cracking
  1. Ethyne molecule is formed when two carbon atoms join together to form a sigma bond by:
  • (A) sp-s overlap
  • (B) 2py-2py overlap
  • (C) sp³-sp³ overlap
  • (D) sp-sp overlap
    Answer: (D) sp-sp overlap
  1. Symmetrical alkanes can be produced by:
  • (A) Sabatier Sender’s Reaction
  • (B) Reduction Reaction
  • (C) Hydrogenolysis Reaction
  • (D) Kolbe’s Electrolytic Reaction
    Answer: (D) Kolbe’s Electrolytic Reaction
  1. The catalyst used for the preparation of acrylonitrile is:
  • (A) Cu₂Cl₂ and NH₄Cl
  • (B) Cu₂Cl₂ and NH₄OH
  • (C) Al₂O₃ and NH₄Cl
  • (D) Cu₂Cl₂ and Al₂O₃
    Answer: (D) Cu₂Cl₂ and Al₂O₃
  1. When a hydrogen atom is removed from benzene, the group left behind is called:
  • (A) Alkyl group
  • (B) Benzyl group
  • (C) Phenyl group
  • (D) Methyl group
    Answer: (C) Phenyl group
  1. The introduction of an NO₂ group into a benzene ring is called nitration. The nitration of benzene takes place when it is heated with a 1:1 mixture of _ at 50°C-55°C:
  • (A) Conc. HNO₃ and conc. HCl
  • (B) Conc. HNO₃ and H₃PO₄
  • (C) Conc. HNO₃ and conc. Acetic acid
  • (D) Conc. HNO₃ and conc. H₂SO₄
    Answer: (D) Conc. HNO₃ and conc. H₂SO₄
  1. During SN2 reactions, the configuration of the alkyl halide molecule:
  • (A) Gets inverted
  • (B) Depends upon the carbon atom
  • (C) Remains the same
  • (D) Depends upon the electronegativity of the halide
    Answer: (A) Gets inverted
  1. Grignard reagents are prepared by the reaction of magnesium metal with alkyl halides in the presence of:
  • (A) Dry ether
  • (B) Alcohol
  • (C) Sodium-lead alloy
  • (D) Water
    Answer: (A) Dry ether
  1. Methanol is prepared from carbon monoxide and hydrogen. The catalyst used for this reaction is:
  • (A) ZnO + CoO₂
  • (B) ZnO + Ag₂O
  • (C) ZnO + CuO
  • (D) Cr₂O₃ + ZnO
    Answer: (C) ZnO + CuO
  1. Ethanol reacts with ammonia to produce ethylamine. The catalyst used is:
  • (A) ZnCl₂
  • (B) C₆H₅N
  • (C) ThO₂
  • (D) Cr₂O₃
    Answer: (A) ZnCl₂
  1. Dissociation constant of phenol is:
  • (A) ( 1.2 \times 10^{-10} )
  • (B) ( 1.3 \times 10^{10} )
  • (C) ( 1.2 \times 10^{10} )
  • (D) ( 1.3 \times 10^{-10} )
    Answer: (A) ( 1.2 \times 10^{-10} )
  1. **Dry distillation of a mixture of calcium salts of formic acid and acetic acid results in the formation of:**
  • (A) Formaldehyde
  • (B) Calcium acetate
  • (C) Acetaldehyde
  • (D) Sodium acetate
    Answer: (C) Acetaldehyde
  1. Hydrolysis of the cyano group by an aqueous acid results in:
  • (A) Carboxylic acid
  • (B) Cyanohydride
  • (C) Acid amide
  • (D) Formaldehyde
    Answer: (A) Carboxylic acid
  1. Brick red precipitates are formed when aldehydes react with:
  • (A) Sodium borohydride
  • (B) Sodium nitroprusside
  • (C) Sodium bisulfite
  • (D) Fehling’s solution
    Answer: (D) Fehling’s solution

Chemistry MCQs (91–120)

  1. The nature of the amino acid ‘lysine’ is:
  • (A) Neutral
  • (B) Amphoteric
  • (C) Acidic
  • (D) Basic
    Answer: (D) Basic
  1. Which of the following compounds, in the form of aqueous solution, reacts with sodium carbonate to produce carbon dioxide gas?
  • (A) H₃C-COO-C₂H₅
  • (B) H₃C₂-CO-OH
  • (C) H₃C₂-COO-CH₃
  • (D) H₃C₂-COO-C₂H₅
    Answer: (B) H₃C₂-CO-OH
  1. Collagen and albumin are:
  • (A) Simple proteins
  • (B) Polyamides
  • (C) Derived proteins
  • (D) Polysaccharides
    Answer: (A) Simple proteins
  1. Urea is produced by the reaction of liquid ammonia with:
  • (A) CO₂
  • (B) CaO
  • (C) CO
  • (D) C
    Answer: (A) CO₂
  1. The calcium sulpho-aluminate is:
  • (A) Co.Al₂O₃.3CaSO₄.6H₂O
  • (B) 3Ca.Al₂O₃.3CaSO₄.2H₂O
  • (C) 3Ca.Al₂O₃.CaSO₄.2H₂O
  • (D) 3Ca.Al₂O₃.3CaSO₄.6H₂O
    Answer: (D) 3Ca.Al₂O₃.3CaSO₄.6H₂O
  1. The coagulant used in raw water to precipitate suspended impurities is:
  • (A) Caustic soda
  • (B) Alum
  • (C) Lime water
  • (D) Soda ash
    Answer: (B) Alum
  1. The whiteness of recycled newspaper is improved by treating it with:
  • (A) Sodium hydroxide
  • (B) Superoxides
  • (C) Peroxides
  • (D) Normal oxides
    Answer: (C) Peroxides
  1. One mole of any gas at standard temperature and pressure (STP) occupies a volume of:
  • (A) 20.414 dm³
  • (B) 22.414 cm³
  • (C) 22.414 dm³
  • (D) 23.414 dm³
    Answer: (C) 22.414 dm³
  1. The relative abundance of isotopes of elements can be determined by:
  • (A) Mass spectrometry
  • (B) Chromatography
  • (C) X-rays
  • (D) Solvent extraction
    Answer: (A) Mass spectrometry
  1. If given the mass of one substance, we can calculate the volume of another substance and vice versa with the help of a balanced chemical equation. This is called:
  • (A) Mass-mass relationship
  • (B) Mole-volume relationship
  • (C) Mass-mole relationship
  • (D) Mass-volume relationship
    Answer: (D) Mass-volume relationship
  1. Sublimation is used to purify:
  • (A) Ammonium sulfate
  • (B) Benzoic acid
  • (C) Sodium chloride
  • (D) Lead carbonate
    Answer: (B) Benzoic acid
  1. The purity of a substance can be identified by:
  • (A) Sublimation
  • (B) Chromatography
  • (C) Filtration
  • (D) Solvent extraction
    Answer: (B) Chromatography
  1. Which one of the following mathematical expressions represents Avogadro’s law?
  • (A) ( V = RnT/P ) (when T and n are constant)
  • (B) ( V = RnT ) (when P and n are constant)
  • (C) ( V = Rn/P ) (when P, T, and n are constant)
  • (D) ( V = R ) (when P and T are constant)
    Answer: (A) ( V = RnT/P )
  1. The root mean square velocity of gases is inversely proportional to the square root of their:
  • (A) Molar mass
  • (B) Pressure
  • (C) Temperature
  • (D) Volume
    Answer: (A) Molar mass
  1. Plasma is an ionized gas mixture that consists of:
  • (A) Ions and electrons
  • (B) Electrons, ions, and neutral atoms
  • (C) Electrons and neutral atoms
  • (D) Ions and neutral atoms
    Answer: (B) Electrons, ions, and neutral atoms
  1. Which type of force is present in gasoline?
  • (A) Dipole-dipole forces
  • (B) London dispersion forces
  • (C) Dipole-induced dipole forces
  • (D) Hydrogen bonding
    Answer: (B) London dispersion forces
  1. In the structure of NaCl, each Na⁺ is surrounded by:
  • (A) Four Cl⁻ ions
  • (B) Five Cl⁻ ions
  • (C) Eight Cl⁻ ions
  • (D) Six Cl⁻ ions
    Answer: (D) Six Cl⁻ ions
  1. The charge of one gram of electrons is:
  • (A) ( 1.7588 \times 10^{-11} )
  • (B) ( 1.602 \times 10^{-19} )
  • (C) ( 1.7588 \times 10^{11} )
  • (D) ( 1.7588 \times 10^8 )
    Answer: (A) ( 1.7588 \times 10^{-11} )
  1. The ionization energy of a hydrogen atom is:
  • (A) Zero
  • (B) ( 1313.31 \, \text{kJ/mol} )
  • (C) ( 13.13 \, \text{kJ/mol} )
  • (D) ( 1313.31 \, \text{k}^2 \text{J/mol} )
    Answer: (B) ( 1313.31 \, \text{kJ/mol} )
  1. Which quantum number helps to study the orientation of an orbital in space?
  • (A) Principal Quantum Number
  • (B) Magnetic Quantum Number
  • (C) Spin Quantum Number
  • (D) Azimuthal Quantum Number
    Answer: (B) Magnetic Quantum Number
  1. The interionic distance in a crystal lattice of KCl is:
  • (A) 314 pm
  • (B) 95 pm
  • (C) 181 pm
  • (D) 300 pm
    Answer: (C) 181 pm
  1. The number of bonds in a nitrogen molecule is:
  • (A) One ( \sigma ) and two ( \pi )
  • (B) Three ( \sigma ) only
  • (C) One ( \sigma ) and one ( \pi )
  • (D) Two ( \sigma ) and one ( \pi )
    Answer: (A) One ( \sigma ) and two ( \pi )
  1. Which one of the following molecules has zero dipole moment?
  • (A) NH₃
  • (B) BF₃
  • (C) CHCl₃
  • (D) H₂O
    Answer: (B) BF₃
  1. A spontaneous process is:
  • (A) Unidirectional and irreversible
  • (B) Unidirectional and a real process
  • (C) Irreversible and a real process
  • (D) All of the above
    Answer: (D) All of the above
  1. The standard enthalpy of solution of NH₄Cl is:
  • (A) ( +16.2 \, \text{kJ/mol} )
  • (B) ( +4.98 \, \text{kJ/mol} )
  • (C) ( -25.0 \, \text{kJ/mol} )
  • (D) ( +26.0 \, \text{kJ/mol} )
    Answer: (A) ( +16.2 \, \text{kJ/mol} )

116

. The ( K_c ) has the following units for the reaction ( H_2(g) + I_2(g) ⇋ 2HI(g) ):

  • (A) ( \text{mol}^3 \text{dm}^{-6} )
  • (B) ( \text{mol}^{-3} \text{dm}^6 )
  • (C) ( \text{mol} \text{dm}^{-3} )
  • (D) No unit
    Answer: (D) No unit
  1. 0.1 mole of acetic acid has been dissolved per dm³ of solution. The percentage ionization of acetic acid will be:
  • (A) 13
  • (B) 1.3
  • (C) 15
  • (D) 0.1
    Answer: (B) 1.3
  1. Solubility of ( Ce_2(SO₄)_3 ):
  • (A) Increases with temperature
  • (B) Shows exceptional behavior
  • (C) Decreases with temperature
  • (D) Remains constant
    Answer: (C) Decreases with temperature
  1. Seawater has ( 5.65 \times 10^{-3} \, g ) of dissolved oxygen in one kilogram of water. Concentration of ( O_2 ) in parts per million is:
  • (A) 5.65
  • (B) 5.20
  • (C) 7.69
  • (D) 4.11
    Answer: (A) 5.65
  1. Metallic conduction involves the relatively free movement of _ throughout the metallic lattice:
  • (A) Atoms
  • (B) Electrons
  • (C) Molecules
  • (D) Ions
    Answer: (B) Electrons

Biology MCQs (121–150)

  1. Which of the following receptors produce a sensation of pain?
  • (A) Mechanoreceptors
  • (B) Chemoreceptors
  • (C) Nociceptors
  • (D) Thermoreceptors
    Answer: (C) Nociceptors
  1. When your finger accidentally gets caught in a door, the pain message is sent to your brain through:
  • (A) Homeostasis
  • (B) Caffeine
  • (C) Sensory receptors
  • (D) The medulla
    Answer: (C) Sensory receptors
  1. The neck has _ type of joint:
  • (A) Ball and socket
  • (B) Hinge
  • (C) Pivot
  • (D) Fibrous
    Answer: (C) Pivot
  1. The end product of hemoglobin breakdown is:
  • (A) Creatinine
  • (B) Hypoxanthin
  • (C) Bilirubin
  • (D) Xanthin
    Answer: (C) Bilirubin
  1. In what direction can DNA polymerase work when catalyzing the addition of nucleotide monomers to build a strand of DNA?
  • (A) From the 5′ toward the 3′ end of the new strand being assembled
  • (B) From replication centers in two directions called replication forks
  • (C) From the 3′ to the 5′ end of the strand being assembled
  • (D) In both directions if DNA ligase is present
    Answer: (A) From the 5′ toward the 3′ end of the new strand being assembled
  1. Which bond is the potential source of chemical energy for cellular activities?
  • (A) C-N
  • (B) C-H
  • (C) C-O
  • (D) H-O
    Answer: (B) C-H
  1. Sharks and rays are included in the class:
  • (A) Cyclostomata
  • (B) Osteichthyes
  • (C) Chondrichthyes
  • (D) Tetrapoda
    Answer: (C) Chondrichthyes
  1. In what stage of aerobic respiration are 2-carbon molecules oxidized completely to carbon dioxide?
  • (A) Glycolysis
  • (B) Krebs cycle
  • (C) ETC
  • (D) Calvin cycle
    Answer: (B) Krebs cycle
  1. Which of the following does not have specialized respiratory organs?
  • (A) Hydra
  • (B) Cockroach
  • (C) Birds
  • (D) Both A and B
    Answer: (A) Hydra
  1. Hummingbirds belong to the category:
  • (A) Heterotherms
  • (B) Ectotherms
  • (C) Endotherms
  • (D) None of these
    Answer: (C) Endotherms
  1. Syphilis is caused by:
  • (A) Neisseria gonorrhoeae
  • (B) Treponema pallidum
  • (C) Cats worm
  • (D) Herpes simplex
    Answer: (B) Treponema pallidum
  1. In moths, males are:
  • (A) Heterogametic
  • (B) Homogametic
  • (C) Dieogametic
  • (D) Both B and C
    Answer: (A) Heterogametic
  1. When carbon dioxide pressure increases, the capacity of hemoglobin to hold oxygen:
  • (A) Increases many folds
  • (B) Remains constant
  • (C) Decreases
  • (D) Is doubled
    Answer: (C) Decreases
  1. The soluble part of the cytoplasm is termed as:
  • (A) Cisternae
  • (B) Endocytosis
  • (C) Cytosol
  • (D) Both A and B
    Answer: (C) Cytosol
  1. Name the enveloped RNA virus that causes infusion hepatitis:
  • (A) HBV
  • (B) HCV
  • (C) HAV
  • (D) None of these
    Answer: (B) HCV
  1. In general, asexual reproduction is common in:
  • (A) Humans
  • (B) Deuteromycota
  • (C) Basidiomycota
  • (D) Basidiospores
    Answer: (B) Deuteromycota
  1. Name the vertebrates that are without jaws:
  • (A) Osteichthyes
  • (B) Chondrichthyes
  • (C) Cyclostomata
  • (D) None of these
    Answer: (C) Cyclostomata
  1. The total inside capacity of lungs of adult humans when fully inflated is:
  • (A) 5 ml
  • (B) 500 ml
  • (C) 50 ml
  • (D) 5000 ml
    Answer: (D) 5000 ml
  1. Which of the following belong to collenchyma cells?
  • (A) Fibers
  • (B) Sclereids
  • (C) Vessels
  • (D) None of these
    Answer: (A) Fibers
  1. Which of the following promotes both leaf and fruit growth?
  • (A) Auxins
  • (B) Abscisic acid
  • (C) Gibberellins
  • (D) Ethane
    Answer: (C) Gibberellins
  1. Name the external factor of growth in plants:
  • (A) Carbon dioxide
  • (B) Hormones
  • (C) Water
  • (D) Nutrition
    Answer: (C) Water
  1. The genes of blue opsin are present on:
  • (A) Autosome 9
  • (B) Autosome 1
  • (C) Autosome 7
  • (D) Autosome 3
    Answer: (C) Autosome 7
  1. The dew drops on the tips of grass leaves are an example of:
  • (A) Infestation
  • (B) Exudation
  • (C) Bleeding
  • (D) Imbibition
    Answer: (B) Exudation
  1. Which of the following modifies proteins and lipids by adding carbohydrates?
  • (A) Golgi apparatus
  • (B) Plasma membrane
  • (C) Polysome
  • (D) None of these
    Answer: (A) Golgi apparatus
  1. Which of the following are spiral-shaped bacteria?
  • (A) Cocci
  • (B) Pseudomonas
  • (C) Bacilli
  • (D) Vibrio
    Answer: (D) Vibrio
  1. Which of the following is used for lowering blood cholesterol?
  • (A) Neurospora
  • (B) Aspergillus
  • (C) Griseofulvin
  • (D) Lovastatin
    Answer: (D) Lovastatin
  1. Which of the following are called placental mammals?
  • (A) Prototheria
  • (B) Metatheria
  • (C) Eutheria
  • (D) All of these
    Answer: (C) Eutheria
  1. The attraction among water molecules, which holds water together, is called:
  • (A) Tension
  • (B) Cohesion
  • (C) Adhesion
  • (D) Imbibition
    Answer: (B) Cohesion
  1. Pick the paratonic movement from the following:
  • (A) Nastic
  • (B) Growth
  • (C) Turgor
  • (D) Tactic
    Answer: (D) Tactic
  1. It controls several automatic functions like breathing, heart rate, and blood pressure:
  • (A) Midbrain
  • (B) Medulla
  • (C) Pons
  • (D) Cerebellum
    Answer: (B) Medulla

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