pH and Solubility Practice Test

The solubility decreases because HCl is a strong electrolyte that screens charges and forces ions to recombine into the solid.

The solubility increases because $\text{H}^+$ reacts with $\text{CO}_3^{2-}$ to form $\text{HCO}_3^-$ and $\text{H}_2\text{CO}_3$, lowering $[\text{CO}_3^{2-}]$ and shifting dissolution forward.

The solubility decreases because adding acid increases $[\text{CO}_3^{2-}]$ through the common-ion effect, shifting dissolution backward.

The solubility stays the same because HCl acts as a buffer that keeps $[\text{CO}_3^{2-}]$ constant in solution.

The solubility stays the same because $K_{sp}$ is constant and pH cannot affect equilibrium positions for ionic solids.