Question

1. Consider the following system at equilibrium where H° = -198 kJ/mol, and K_c = 34.5 , at 1150 K.
2 SO₂(g) + O₂(g)  2 SO₃(g). When 0.11 moles of SO₃(g) are added to the equilibrium system at constant temperature:The value of K_c Increases, Decreases, remains the same
The value of Q_c is greater than, is equal to, is less than kc.
The reaction must

run in the forward direction to restablish equilibrium.
run in the reverse direction to restablish equilibrium.
remain the same. It is already at equilibrium.

The concentration of O₂will increase, decrease, remains the same.

2. Consider the following system at equilibrium where H° = -16.1 kJ, and K_c = 154, at 298 K.
2NO(g) + Br₂(g) 2NOBr(g)
When 0.39 moles of Br₂(g) are removed from the equilibrium system at constant temperature:
The value of K_c Increases, Decreases, remains the same
The value of Q_c is greater than, is equal to, is less than kc.
The reaction must

run in the forward direction to restablish equilibrium.
run in the reverse direction to restablish equilibrium.
remain the same. It is already at equilibrium.

The concentration of NO will increase, decrease, remains the same.

Answer 1

Answer 1

The reaction involved is

2 SO2(g) + O2(g) <-------> 2 SO3(g)

On addition of SO3 at constant temperature.

K_cremains same.

Reason : K_c remains same as far as temperature remains constant.

Q_c is greater than K_c

Reason: Q_c is given by [SO3]²/[SO2]²[O2]

So, increase in products, increases Qc.

The reaction must run in reverse direction to establish equilibrium.

Reason: The product has been increased. So, to undo the change, product must be decomposed to reactants.

Concentration of O2 will increase

Reason: Reaction will shift towards reactants and hence, their amount will increase.

Answer 2

The reaction involved is

2NO (g) + Br2(g) <-------> 2NOBr(g)

On removal of Br2 at constant temperature.

Kc remains same.

Reason : Kc remains same as far as temperature remains constant.

Qc is greater than Kc

Reason: Qc is given by [NOBr]²/[NO]²[Br2]

So, decrease in products, increases Qc.

The reaction must run in reverse direction to establish equilibrium.

Reason: The reactant, Br2, has been decreased. So, to undo the change, product must be decomposed to get the reactants.

Concentration of NO will increase
Reason: Reaction will shift towards reactants and hence, their amount will increase.

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