Question

Consider the following reaction where Kc = 1.29×10-2 at 600 K: COCl2 (g) CO (g) + Cl2 (g) A reaction mixture was found to contain 0.104 moles of COCl2 (g), 4.66×10-2 moles of CO (g), and 3.76×10-2 moles of Cl2 (g), in a 1.00 liter container. Indicate True (T) or False (F) for each of the following:
1. In order to reach equilibrium COCl2(g) must be consumed.
A. True B. False
2. In order to reach equilibrium Kc must increase.
A. True B. False
3. In order to reach equilibrium CO must be consumed.
A. True B. False
4. Qc is greater than Kc.
A. True B. False
5. The reaction is at equilibrium. No further reaction will occur.
A. True B. False

Answer 1

Answer:

1. In order to reach equilibrium COCl₂(g) must be consumed.

B. False

2. In order to reach equilibrium Kc must increase.

B. False .

3. In order to reach equilibrium CO must be consumed.

A. True.

4. Qc is greater than Kc.

A. True

5. The reaction is at equilibrium. No further reaction will occur.

B. False.

Explanation:

Based on the reaction:

COCl₂(g) → CO (g) + Cl₂(g)

And Kc is defined as:

Kc = 1.29x10⁻² = [CO] [Cl₂] / [COCl₂]

Molar concentrations of each species are:

[COCl₂] = 0.104 moles of COCl₂ / 1L = 0.104M

[CO] = 4.66×10⁻² moles of CO / 1L = 4.66×10⁻²M

[Cl₂] = 3.76×10⁻² moles of Cl₂ / 1L = 3.76×10⁻²M

Replacing in Kc formula:

4.66×10⁻²M × 3.76×10⁻²M / 0.104M = 1.68x10⁻²

As the concentrations are not in equilibrium, 1.68x10⁻² is defined as the reaction quotient, Qc.

As Qc > Kc, the reaction will shift to the left producing more COCl₂ and consuming CO and Cl₂. Thus

1. In order to reach equilibrium COCl₂(g) must be consumed.

B. False

2. In order to reach equilibrium Kc must increase.

B. False . Kc is a constant that never change.

3. In order to reach equilibrium CO must be consumed.

A. True.

4. Qc is greater than Kc.

A. True

5. The reaction is at equilibrium. No further reaction will occur.

B. False. The reaction is in equilibrium when Qc = Kc