1. The aqueous solution of acid conduct electricity because the acid solution have \(\mathrm{H}^{+}\)ions and the movement of these ions helps for the flow of electrical current through the solution.
Hence, the aqueous solution of an acid conduct electricity.
2. During dilution, more of acid dissociates into ions. Thus, concentration of \(\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]\)ions will increase on dilution.
3. Even on increasing \(\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]\)ions, the number of ions per unit volume decreases. Therefore, pH will increase on dilution.
4. (a) \(\mathrm{CO}_{2}\) gas will evolve accompanied by brisk effervescence. \(\mathrm{NaHCO}_{3}(\mathrm{~s})+\mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{NaCl}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{~g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{aq})\)
(b) \(\mathrm{H}_{2}\) gas will evolve accompanied by brisk effervescence.
$$
\mathrm{Zn}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{ZnCl}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\mathrm{q})
$$
