Explain the following. Aqueous solution of $$\text{AlCl}_3$$ behaves acidic towards litmus while that of NaCl not.

PLACEHOLDER ANSWER - the answer is an explanation. $$\text{AlCl}_3$$ is a salt of a weak base, $$\text{Al(OH)}_3$$, and a strong acid, HCl, so it hydrolyses, $$\text{AlCl}_3 + 3\text{H}_2\text{O} \rightleftharpoons \text{Al(OH)}_3 + 3\text{HCl}$$, and the excess $$\text{H}^+$$ turns blue litmus red. NaCl is a salt of a strong acid and a strong base; its ions do not hydrolyse, so its solution is neutral.