WBJEE 2024 Physics & Chemistry Paper

Let's analyze how the addition of the given compounds affects the acidity in both scenarios:(i) $\mathrm{CuSO}_4$ is added to a saturated $(\mathrm{NH}_4)_2\mathrm{SO}_4$ solution:$\mathrm{CuSO}_4$ is a salt that can hydrolyze in solution to form an acidic solution due to the formation of $\mathrm{H}^{+}$ ions. Adding $\mathrm{CuSO}_4$ to a saturated $(\mathrm{NH}_4)_2\mathrm{SO}_4$ solution will contribute additional $\mathrm{H}^{+}$ions, thus increasing the acidity of the solution. (ii) $\mathrm{SbF}_5$ is added to anhydrous HF :$\mathrm{SbF}_5$ is known as a Lewis acid, and when it is added to anhydrous HF (which itself is a weak acid) it forms a highly acidic superacid called fluoroantimonic acid (HSbF_6). This greatly increases the acidity of the mixture due to the high proton-donating ability of the resulting superacid.Therefore, in both cases, the acidity will increase upon the addition of $\mathrm{CuSO}_4$ and $\mathrm{SbF}_5$ to the respective solutions.Correct Option: A - increase, increase