Addition of which of the following substances will increase the solubility of CuCO3 (s) in water ?
CuCO3 ---- Cu^2+ (aq) +2 CO3^2- (aq)
1. Aqueous hydrochloric acid
2. Aqueous sodium carbonate
3. Solid copper (II) carbonate
a) 1 only
b) 2 only
c) 3 only
d) 1 and 3 only
e) 1,2 and 3 only
2 only
1 only
1 only
To determine which substances can increase the solubility of CuCO3 (s) in water, we need to apply the principles of solubility and common ion effect.
CuCO3 dissociates in water to form Cu^2+ (aq) and CO3^2- (aq).
From the given options:
1. Aqueous hydrochloric acid (HCl) dissociates to form H^+ (aq) and Cl^- (aq). The addition of H^+ ions will increase the solubility of CuCO3 (s) by shifting the equilibrium to the right to counterbalance the common ion effect.
2. Aqueous sodium carbonate (Na2CO3) dissociates to form 2 Na^+ (aq) and CO3^2- (aq). The addition of CO3^2- ions will increase the solubility of CuCO3 (s) by shifting the equilibrium to the right.
3. Solid copper (II) carbonate is a reactant rather than an added substance. It will not directly increase the solubility of CuCO3 (s) in water.
Based on this analysis, both options 1 and 2 can increase the solubility of CuCO3 (s) in water. Therefore, the correct answer is:
d) 1 and 3 only
You haven't written the correct equation. It should be
CuCO3(s) ==> Cu^2+(aq) + CO3^2-(aq)
I'll give you a couple of hints.
Adding HCl will react with CO3^2- to form H2O and CO2, thus decreasing CO3^2-. Remember Le Chatelier's Principle--decreasing CO3^2- will drive the reaction which way?
Adding Na2CO3 will increase (CO3^2-). Which way will that drive the reaction.
Adding solid CuCO3. You already have solid CuCO3 present; adding more will have no effect.