Identify product ' $B$ ' in the following sequence of reaction.

$$ \text { Aniline } \xrightarrow[273 \mathrm{~K}]{\mathrm{NaNO}_2+\mathrm{HCl}} \mathrm{~A} \xrightarrow[\Delta]{\mathrm{H}_2 \mathrm{O}} \mathrm{~B}+\mathrm{N}_2 \uparrow $$

Which of the following species acts as strongest oxidising agent?

Identify isoelectronic pair from following.

When 0.01 mole of nonvolatile solute is dissolved in certain solvent calculate the mass of solvent in kg if $\Delta \mathrm{T}_{\mathrm{b}}=0.6 \mathrm{~K}$ and $\mathrm{K}_{\mathrm{b}}$ for solvent= $2 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$