Which of the following compounds is the most stable?

The photochemical chlorination of alkanes is initiated by .....

For the fastest rate of reaction in the given free radical halogenation of cyclohexane,$X_2$ must be:

Anhydrous sodium acetate on heating with sodalime gives

The addition of tetraethyl lead to petrol:

Identify the product $B$ in the following reaction sequence.
$C_2H_5-Br$ $\xrightarrow[\text{Dry ether}]{Mg} A$ $\xrightarrow{CH_3OH} B$