Question

A $100$ $mL$ solution of $CH_3CH_2MgBr$ on treatment with methanol produces $2.24$ $mL$ of a gas at STP. The weight of gas produced is_____ mg. [nearest integer]

Answer 1

$CH_3−CH_2−MgBr+CH_3OH→CH_3−CH_3+MgBr(OCH_3)$

As $2.24$ ml is formed at STP.

Number of moles of ethane gas produced

= $\frac{2.24x}{22.4}$

= $10^{−4} ml$

Mass of ethane produced = $10^{–4} × 30 = 3 × 10^{–3} = 3$ $mg$