The major product (F) in the following reaction is

For a chemical reaction, half-life period $\left(t_{\frac{1}{2}}\right)$ is 10 minutes. How much reactant will be left after 20 minutes if one starts with 100 moles of reactant and the order of the reaction be (i) zero, (ii) one and (iii) two?

Equal volume of two solutions $A$ and $B$ of a strong acid having $\mathrm{pH}=6.0$ and $\mathrm{pH}=4.0$ respectively are mixed together to form a new solution. The pH of the new solution will be in the range

$P$ and $Q$ combines to form two compounds $\mathrm{PQ}_2$ and $\mathrm{PQ}_3$. If $1 \mathrm{~g} ~\mathrm{PQ}{ }_2$ is dissolved in 51 g benzene the depression of freezing point becomes $0 \cdot 8^{\circ} \mathrm{C}$. On the other hand if $1 \mathrm{~g} ~\mathrm{PQ}_3$ is dissolved in 51 g of benzene, the depression of freezing point becomes $0.625^{\circ} \mathrm{C}$. The atomic mass of P and Q are $\left(\mathrm{K}_{\mathrm{f}}\right.$ of benzene $=5 \cdot 1 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1})$