Chemistry Class 11 NCERT Solutions: Chapter 7 Equilibrium Part 1

Chemistry Class 11 NCERT Solutions Chapter 7 Equilibrium Part 1

Q: 1. A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.

(A) What is the initial effect of the change on vapour pressure?

(B) How do rates of evaporation and condensation change initially?

(C) What happens when equilibrium is restored finally and what will be the final vapour pressure?

Answer:

(A) If the volume of the container is suddenly increased, then vapour pressure would decrease initially. This is because the amount of vapour remains the same, but the volume increases suddenly. As a result, the same amount of vapour is distributed in a larger volume.

(B) Since the temperature is constant, the rate of evaporation also remains constant. When the volume of the container is increased, the density of the vapour phase decreases. As a result, the rate of collisions of the vapour particles also decreases. Hence, the rate of condensation decreases initially.

(C) When equilibrium is restored finally, the rate of evaporation becomes equal to the rate of condensation. In this case, only the volume changes while the temperature remains constant. The vapour pressure depends on temperature and not on volume. Hence, final vapour pressure will be equal to the original vapour pressure of the system.

Q: 2. What is Equation for the following equilibrium when the equilibrium concentration of each substance is: Equation

Equation

Answer:

The equilibrium constant Equation for the give reaction is:

Equation

Equation

Equation

Hence, Equation for the equilibrium is Equation

Q: 3. At a certain temperature and total pressure of Equation , iodine vapour contains 40% by volume of I atoms

Equation

Equation for Equation the equilibrium.

Answer:

Partial pressure of I atoms,

Equation

Equation

Equation

Partial pressure of Equation molecules,

Equation

Equation

Equation

Now, for the given reaction,

Equation

Equation

Equation

Q: 4. Write the expression for the equilibrium constant, Equation for each of the following reactions:

(i) Equation

(ii) Equation

(iii) Equation

(iv) Equation

(v) Equation

Answer:

(i) Equation

(ii) Equation

(iii) Equation

(iv) Equation

Equation

(v) Equation

Equation

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