Question

Which compound is needed to increase the molar solubility of ${CaCO}_3\left(s\right)$ in a saturated aqueous solution?

• A. More water
• B. ${CaCO}_3\left(s\right)$
• C. $NaOH$
• D. ${NaHSO}_4$

Answer 1

Answer: (D)

${NaHSO}_4$

Calcium carbonate is sparingly soluble in water. It reacts with sodium hydrogen sulphate to form sodium carbonate and calcium hydrogen sulphate which are soluble in water.
Hence, in the dissociation equilibrium reaction of the calcium carbonate, calcium and carbonate ions are removed in the form of soluble salts. Hence, the molar solubility of calcium carbonate increases when sodium hydrogen sulphate is added.