Use the following information to answer questions $14$ and $15.$

Sulfur dioxide gas, $S{O}_2(g),$ in air contributes to the formation of acid rain. The concentration of $S{O}_2(g)$ in air can be determined by dissolving the $S{O}_2(g)$ in water and then titrating the solution produced with a standard solution of potassium permanganate, $KMn{O}_4(aq).$ The titration reaction can be represented by the following unbalanced equation.

$(()2)4$

During the titration, a student would expect to observe

A$.$ an increase in acidity

B$.$ a decrease in solution volume

C$.$ a decrease in the electrical conductivity

D$.$ an increase in the intensity of the purple colour

A $150mL$ sample of $S{O}_2(aq)$ required $31\mathrm{.}5mL$ of $0\mathrm{.}0100mo\frac{l}{L}KMn{O}_4(aq)$ to completely react. The concentration of $S{O}_2(aq)$ in the sample was

A$.,0\mathrm{.}840$mmo$\frac{l}{L}$

B$.,2\mathrm{.}10$mmo$\frac{l}{L}$

C$.5\mathrm{.}25$mmo$\frac{l}{L}$

D$.,118$mmo$\frac{l}{L}$