Identify the major product of the dehydrohalogenation of $CH_3-CH_2-CH(Br)-CH_3$ using an alcoholic base.

$CH_3CH(Br)CH_2CH_3 + \text{alc. } KOH \to$ ?

At $30\,^\circ C$,the rate of reaction between $2$-bromobutane and $OH^-$ in $75\%$ ethanol and $25\%$ water is given by: $\text{Rate} = 3.20 \times 10^{-5} [2\text{-bromobutane}][OH^-] + 1.5 \times 10^{-6} [2\text{-bromobutane}]$. If $[OH^-] = 1.0\,M$,what percentage of the reaction proceeds via the $S_N2$ mechanism?

When benzyl chloride is treated with ethanolic $KCN$,the major product formed is

$3$-Phenylpropene on reaction with $HBr$ gives (as a major product)

Consider the reaction sequence given below. Which of the following statements is true?