JEE Main 2022 — Alcohols Phenols and Ethers Question with Solution

Alcohols on reaction with Grignard reagent forms hydrocarbons.This is due to the presence of active hydrogen in alcohols and here grignard reagent acts as a base.

When any alcohol is treated with methyl magnemsium iodide the hydrocarbon formed should be methane gas.

$\mathrm{ROH}+{\mathrm{CH}}_3\mathrm{MgI}\to \mathrm{ROMgI}+{\mathrm{CH}}_4\left(\mathrm{g}\right)$

Number of moles of ${\mathrm{CH}}_4=$ Number of moles of $\mathrm{ROH}$

$\Rightarrow \frac{\mathrm{Volume}\left(\mathrm{Litres}\right) \mathrm{of} \mathrm{the} \mathrm{gas}}{22400}=\frac{\mathrm{mass} \mathrm{of} \mathrm{the} \mathrm{gas}}{\mathrm{Molecular} \mathrm{mass} \mathrm{of} \mathrm{the} \mathrm{gas}}$ (Assuming $\mathrm{NTP}$ Condition)

$\Rightarrow \frac{3.1}{22400}=\frac{4.5\times {10}^{-3}}{\mathrm{Molecular} \mathrm{mass} \mathrm{of} \mathrm{the} \mathrm{gas}}$

$\Rightarrow \mathrm{MM}=32.51$

$=33$$\mathrm{g}/\mathrm{mol}$