Given the reaction:

Cu2+(aq) + S2-(aq) CuS(s)
What will happen (a) if CuSO4(aq) is added? And (b) if Na2SO4(aq) is added?

A. (a) Nothing; (b) Less product will form
B. (a) Less product will form; (b) Nothing
C. (a) Nothing; (b) More product will form
D. (a) More product will form; (b) Nothing

Your thinking?

not sure. can you show me how to work through it?

To determine what will happen when CuSO4(aq) is added and when Na2SO4(aq) is added, we need to consider the effect of these substances on the equilibrium of the reaction.

(a) If CuSO4(aq) is added:
CuSO4(aq) can dissociate into Cu2+(aq) and SO4^2-(aq). Since Cu2+(aq) is one of the reactants in the reaction, adding CuSO4(aq) will increase the concentration of Cu2+(aq) in the solution. According to Le Chatelier's principle, the system will shift in the direction that reduces the concentration of Cu2+(aq) to re-establish equilibrium. This means more CuS(s) will be formed until a new equilibrium is reached. Therefore, adding CuSO4(aq) will result in more product formation.

(b) If Na2SO4(aq) is added:
Na2SO4(aq) can dissociate into 2 Na+(aq) and SO4^2-(aq). However, neither Na+(aq) nor SO4^2-(aq) are directly involved in the reaction. Therefore, adding Na2SO4(aq) will not have any effect on the equilibrium of the reaction. No shift in the reaction will occur, and the amount of product formed will remain unchanged.

Based on the above explanation, the correct answer is:

D. (a) More product will form; (b) Nothing