Among the following rules,the one which is applied in the given reaction is:
$CH_3-CH(Br)-CH_2-CH_3 \xrightarrow{Alc. KOH}$
$I. CH_3-CH=CH-CH_3$ (major product)
$II. CH_2=CH-CH_2-CH_3$ (minor product)

$A$ primary alkyl halide $(a)$ with molecular formula $C_{4}H_{9}Br$ reacts with alcoholic $KOH$ to give compound $(b)$. Compound $(b)$ reacts with $HBr$ to give compound $(c)$,which is an isomer of $(a)$. When $(a)$ reacts with sodium metal,it gives compound $(d)$ with molecular formula $C_{8}H_{18}$,which is different from the compound formed when $n$-butyl bromide reacts with sodium. Identify the structural formula of $(a)$ and write the equations for all the reactions.

The reaction:
$CH_3CH_2I + KOH_{(aq)} \to CH_3CH_2OH + KI$
is classified as :

What is the major product formed in the following reaction?

Major products $A$ and $B$ formed in the following reaction sequence are:

$A$ compound $(a)$,$C_8H_9Br$,gives a white precipitate when heated with alcoholic $AgNO_3$. Oxidation of $(a)$ gives an acid $(b)$. The acid $(b)$,$C_8H_6O_4$,easily forms an anhydride on heating. Identify the compound $(a)$.