Question

Part A

Which graph represents what happens to the solubility of BaCO3 as HNO3 is added?

Part B

Which graph represents what happens to the BaCO3 solubility as Na2CO3 is added?

Part C

Which represents what happens to the BaCO3 solubility as NaNO3 is added?

Answer 1

Part A

$2 HNO_3 + BaCO_3 \rightleftharpoons Ba(NO_3)_2+H_2O+CO_2$

Thus barium carbonate (solubility 24 mg/L at 25 ^oC) reacts with nitric acid to form barium nitrate (solubility 10.5 g/100 mL at 25 ^oC) and water and carbon dioxide.

Hence, the solubility of barium carbonate increases. It is represented by last graph.

Part B

Sodium carbonate provides carbonate ion which acts as a common ion to barium carbonate and suppresses the equilibrium $BaCO_3 \rightleftharpoons Ba^{2+} + CO_3^{2-}$

Hence, the solubility of barium carbonate decreases. It is represented by first graph.

Part C:

There is no reaction between barium carbonate and sodium nitrate. Also there is no common ion. Hence, there is no change in the solubility of barium carbonate. It is represented by middle graph.