Identify the reagent involved in Sandmeyer reaction.

The solubility of AgBr is $7.1 \times 10^{-7} \mathrm{~mol} \mathrm{dm}^{-3}$. Calculate its solubility product at the same temperature.

Identify the product ' B ' in the following sequence of reactions.

$$ \text { Methylpropanoate } \xrightarrow[\text { dil. } \mathrm{NaOH}]{\Delta} \mathrm{A} \xrightarrow[\text { Conc. } \mathrm{HCl}]{\mathrm{H}^{+}} \mathrm{B} $$

Which from following functional groups has highest priority order for naming the poly functional compound?