Which of the following compounds will evolve hydrogen on treatment with metal?

Based on the provided reaction scheme,determine the total number of stereoisomers of $B$.

Consider the following methods $:$
$I$: Hydration of olefins
$II$: Hydrolysis of alkyl halide
$III$: Reduction of carbonyl compounds
Which of these can be used to prepare alcohols ?

In which one of the following conversions is phosphorus pentachloride $(PCl_5)$ used as a reagent?

Identify product $B$ in the following reaction sequence:
$(CH_3)_2C=C(CH_3)_2$ $\xrightarrow{X_2, H_2O} A$ $\xrightarrow{OH^{-}} B$

$1.12 \, mL$ of a gas is produced at $STP$ by the action of $4.12 \, mg$ of alcohol with methyl magnesium iodide. The molecular mass of the alcohol is: