MHTCET 23 Apr 2025 Shift 2 Paper

Concept:Salts hydrolyse in water to give acidic, basic, or neutral solutions depending on the strength of the parent acid and base.Explanation:$\mathrm{NH}_{4}\mathrm{NO}_{3}$ is a salt of a weak base ($\mathrm{NH}_{4}\mathrm{OH}$) and a strong acid ($\mathrm{HNO}_{3}$), so its solution is acidic.$\mathrm{Na}_{2}\mathrm{CO}_{3}$ is a salt of a strong base ($\mathrm{NaOH}$) and a weak acid ($\mathrm{H}_{2}\mathrm{CO}_{3}$).The carbonate ion undergoes hydrolysis as: $\mathrm{CO}_{3}^{2-} + \mathrm{H}_{2}\mathrm{O} \rightleftharpoons \mathrm{HCO}_{3}^{-} + \mathrm{OH}^{-}$.This produces $\mathrm{OH}^{-}$ ions, making the solution basic.$\mathrm{NaNO}_{3}$ is a salt of a strong acid and a strong base, so its solution is neutral.$\mathrm{CuSO}_{4}$ is a salt of a weak base ($\mathrm{Cu(OH)}_{2}$) and a strong acid ($\mathrm{H}_{2}\mathrm{SO}_{4}$), so its solution is acidic.Therefore, only $\mathrm{Na}_{2}\mathrm{CO}_{3}$ forms a basic solution.Answer:Option B: $\mathrm{Na}_{2}\mathrm{CO}_{3}$