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

$$\mathrm{C}_2 \mathrm{H}_5-\mathrm{Br} \xrightarrow[\text { Dry ether }]{\mathrm{Mg}} \mathrm{~A} \xrightarrow{\mathrm{CH}_3 \mathrm{OH}} \mathrm{~B}$$

Identify the major product ( $99 \%$ ) formed when $\left(\mathrm{CH}_3\right)_3 \mathrm{CH}$ is treated with $\mathrm{Br}_2$ in UV light.

Which of the following is NOT obtained when a mixture of methyl bromide and ethyl bromide is treated with sodium metal in presence of dry ether?

Which from following alkyl substituted alkenes is most stable?