Experiment 7.1: Electrical Conductivity of Solutions

Experiment 7.1: Electrical Conductivity of Solutions

Determine which solutions conduct electricity

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Background Information

A compound that dissolves in water to give ions is called an electrolyte. These ions allow the solution to conduct electric current.

Required Materials

  • Battery
  • Beaker
  • Two electrodes
  • Bulb
  • Bulb holder
  • Switch or key
  • Connecting wires with crocodile clips
  • Distilled water
  • Sugar solution
  • Sodium chloride solution

Procedure

1

Fill Beaker

Fill a beaker approximately half with the given solution.

2

Insert Electrodes

Insert two electrodes into the beaker so that they remain separate from each other.

3

Connect Circuit

Connect one electrode to the battery through a switch, and the other electrode to the battery through the bulb.

4

Test Conductivity

Turn on the switch. If the bulb lights up, the solution is an electrolyte because electricity is passing through it. If the bulb does not light up, the solution is a non-electrolyte.

5

Repeat for All Solutions

Repeat the same procedure for all given solutions and note the observations.

Short Questions & Answers

1. What is an electrolyte?
Answer: A compound that dissolves in water to give ions and allows electric current to pass through the solution.
2. Why does distilled water not conduct electricity?
Answer: Distilled water does not contain ions, which are necessary for conducting electricity.
3. What happens when sugar solution is tested for electrical conductivity?
Answer: The bulb does not light up because sugar solution does not dissociate into ions and is a non-electrolyte.
4. Why does sodium chloride solution conduct electricity?
Answer: Sodium chloride solution contains Na+ and Cl- ions that can move freely and conduct electric current.
5. What is the difference between an electrolyte and a non-electrolyte?
Answer: Electrolytes conduct electricity in solution form due to presence of ions, while non-electrolytes do not conduct electricity as they don’t form ions.

Multiple Choice Questions (10)

1. Which of the following solutions will conduct electricity?
Correct Answer: Sodium chloride solution
2. What causes a solution to conduct electricity?
Correct Answer: Presence of free ions
3. Which of the following is a non-electrolyte?
Correct Answer: Alcohol
4. In the conductivity test, if the bulb glows brightly, it indicates:
Correct Answer: The solution is a good conductor
5. Which of the following substances will not conduct electricity in its solid state?
Correct Answer: Sodium chloride
6. Which ion is responsible for electrical conductivity in common salt solution?
Correct Answer: Na+ and Cl- ions
7. Why do ionic compounds conduct electricity only in molten or aqueous state?
Correct Answer: Their ions become free to move
8. Which of the following will show the highest electrical conductivity?
Correct Answer: Sea water
9. What happens to the electrical conductivity of a solution when its concentration increases?
Correct Answer: It increases
10. Which of the following acids is a strong electrolyte?
Correct Answer: Hydrochloric acid