Q. For the reaction 2A ⇌ B + C, if the initial concentration of A is 0.5 M and at equilibrium, [B] = 0.2 M, what is the equilibrium concentration of A?
Q. For the reaction 2A ⇌ B + C, if the initial concentration of A is 0.5 M and at equilibrium, the concentration of B is 0.2 M, what is the equilibrium concentration of A?
Q. For the reaction 2NO(g) + O2(g) ⇌ 2NO2(g), if the initial concentrations are [NO]=0.5 M and [O2]=0.5 M, what will be the equilibrium concentration of NO2 if Kc=4?
A.0.1 M
B.0.2 M
C.0.3 M
D.0.4 M
Solution
Using ICE table and Kc expression, we find [NO2] at equilibrium to be 0.2 M.
Q. For the reaction A(g) ⇌ B(g), if the concentration of B is increased, what will happen to the concentration of A at equilibrium?
A.Increase
B.Decrease
C.Remain the same
D.Cannot be determined
Solution
According to Le Chatelier's principle, increasing the concentration of a product will shift the equilibrium to the left, decreasing the concentration of A.
Q. For the reaction CO(g) + 2H2(g) ⇌ CH3OH(g), what will happen if the pressure is increased?
A.Equilibrium shifts to the left
B.Equilibrium shifts to the right
C.No change in equilibrium
D.Equilibrium constant increases
Solution
Increasing pressure favors the side with fewer moles of gas. In this case, the right side has 1 mole of CH3OH compared to 3 moles on the left, so the equilibrium shifts to the right.
Correct Answer: B — Equilibrium shifts to the right
Q. For the reaction N2(g) + 3H2(g) ⇌ 2NH3(g), if the concentration of NH3 is increased, what will happen to the equilibrium?
A.Shift to the right
B.Shift to the left
C.No change
D.Increase the rate of reaction
Solution
According to Le Chatelier's principle, increasing the concentration of a product (NH3) will shift the equilibrium to the left to counteract the change.
Q. For the reaction N2(g) + 3H2(g) ⇌ 2NH3(g), what happens if the volume of the container is decreased?
A.Equilibrium shifts to the left
B.Equilibrium shifts to the right
C.No change in equilibrium
D.Equilibrium constant changes
Solution
Decreasing the volume increases the pressure, and according to Le Chatelier's principle, the equilibrium will shift towards the side with fewer moles of gas, which is the right side in this case.
Correct Answer: B — Equilibrium shifts to the right
Q. For the reaction N2(g) + 3H2(g) ⇌ 2NH3(g), what happens to the equilibrium position if the volume of the container is decreased?
A.Equilibrium shifts to the left
B.Equilibrium shifts to the right
C.No change in equilibrium
D.Equilibrium shifts in both directions
Solution
According to Le Chatelier's principle, decreasing the volume increases the pressure, and the equilibrium will shift towards the side with fewer moles of gas, which is the right side (2 moles of NH3).
Correct Answer: B — Equilibrium shifts to the right
Q. For the reaction N2(g) + 3H2(g) ⇌ 2NH3(g), what happens to the equilibrium position if the pressure is increased?
A.Shifts to the left
B.Shifts to the right
C.No change
D.Depends on temperature
Solution
Increasing the pressure shifts the equilibrium towards the side with fewer moles of gas. In this case, the right side has 2 moles of NH3 compared to 4 moles of reactants.
