The following reaction is supposed to take place through the $S_N1$ mechanism: $CH_3-C(Ph)(OH)-CH_2-CH_3 \xrightarrow{HI} \text{products}$. If the configuration of the substrate is $D$,then the configuration of the products will be:

An alkyl bromide $(A)$ forms a Grignard reagent which on treatment with water yields $n$-hexane. When $(A)$ is treated with sodium in dry ether,$4,5$-diethyloctane is formed. The structure of $(A)$ is:

How many of the four monochloro derivatives of $(CH_3)_2CHCH_2CH_3$ are optically active?

Consider the above chemical reaction. Product $A$ is:

For the following compounds,the correct statement$(s)$ with respect to nucleophilic substitution reactions is(are):
$I$: Benzyl bromide $(C_6H_5CH_2Br)$
$II$: Cyclohexylmethyl bromide $(C_6H_{11}CH_2Br)$
$III$: tert-Butyl bromide $((CH_3)_3CBr)$
$IV$: $1-$Phenylethyl bromide $(C_6H_5CH(CH_3)Br)$
$A$. $I$ and $III$ follow $S_{N}1$ mechanism
$B$. $I$ and $II$ follow $S_{N}2$ mechanism
$C$. Compound $IV$ undergoes inversion of configuration
$D$. The order of reactivity for $I$,$III$ and $IV$ is: $IV > I > III$

Vicinal and geminal dihalides can be distinguished by using: