Test Session Chapter 6 Equilibria (9th Chemistry)
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Equilibria Test
Class 9th – Chemistry (SNC) – Chapter 6
2025@everexams.com
Paper Date:
Time: 60 minutes
Total Marks: 50
Paper Type: Objective + Subjective
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Multiple Choice Questions 10×1=10
1
What condition should be met for the reversible reaction to achieve the state of equilibrium?
2
The colour of anhydrous cobalt chloride solid is:
3
In a chemical reaction, the substances that combine are called:
4
Such reactions which continue in both directions are called:
5
The forward reaction takes place from:
6
The colour of hydrated cobalt chloride solid is:
7
What happens to the equilibrium constant (K) when the temperature of a system at dynamic equilibrium is increased?
Hint: Consider Le Chatelier’s principle – how equilibrium shifts with temperature changes
8
What is the effect of adding an inert gas to a system at dynamic equilibrium?
9
Which type of reaction does not go to completion?
10
For the following reaction, equilibrium mixture will contain: N₂O₄ ⇌ 2NO₂, Kc = 0.211
N2O4 ⇌ 2NO2
Short Answer Questions 15×2=30
1
How can you get the maximum yield in a reversible reaction?
ii
Why are some reactions irreversible while others are reversible? (Constructed Response Question)
iii
How is dynamic equilibrium different from static equilibrium?
iv
How can you decrease the time to attain the position of equilibrium in a reversible reaction?
v
Define irreversible reaction.
vi
What is meant by reversible reaction?
Reactants ⇌ Products
vii
Differentiate between reversible and irreversible reaction.
Reversible
viii
Why reversible reaction never goes to completion?
ix
What is copper sulfate pentahydrate?
x
Define dynamic equilibrium.
xi
How dynamic equilibrium is established?
xii
What is meant by static equilibrium? Give example.
xiii
Elaborate the example of dynamic equilibrium.
xiv
Elaborate an example of dynamic equilibrium which exists in this world between the three physical states of water. Exercise
Hint: Consider water ⇌ ice ⇌ vapor equilibrium at 0°C and 100°C
xv
Dinitrogen tetraoxide (N₂O₄) is a colourless gas. It slowly changes to brown coloured nitrogen dioxide (NO₂) at 100°C. Predict how the colour of the mixture will change if N₂O₄ is kept in a sealed flask at 100°C. Exercise
N2O4 (colorless) ⇌ 2NO2 (brown)
Detailed Answer Questions (Answer any 2) 2×5=10
1
Define reversible reaction. Write four properties.
Key Points: Forward and backward reactions, Equilibrium state, Dynamic nature, Concentration changes
A + B ⇌ C + D
2
Differentiate between reversible and irreversible reactions.
Reversible vs Irreversible
3
How dynamic equilibrium of the reaction can be established?
Key Concepts:
1. Rate of forward reaction = Rate of backward reaction
2. Concentrations remain constant
3. Macroscopic properties remain unchanged
4. Dynamic nature at molecular level
