Which of the following compounds has maximum covalent character?

Calculate the percent dissociation of 0.02 m solution if its freezing point depression is 0.046 K .

$\left[\mathrm{K}_{\mathrm{f}}\right.$ for water $\left.=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1} ; \mathrm{n}=2\right]$

For the reaction, $\mathrm{NO}_{2(\mathrm{~g})}+\mathrm{CO}_{(\mathrm{g})} \longrightarrow \mathrm{NO}_{(\mathrm{g})}+\mathrm{CO}_{2(\mathrm{~g})}$, rate of formation of $\mathrm{NO}_{(\mathrm{g})}$ is $\mathrm{Y} \mathrm{mol} \mathrm{dm} \mathrm{ds}^{-1}$. Find the rate of disappearance of $\mathrm{CO}_{(\mathrm{g})}$.

Identify the compound formed by action of chromyl chloride on toluene in presence of $\mathrm{CS}_2$ and hydrolysed further?