Grignard reagent RMgBr ( P ) reacts with water and forms a gas (Q). One gram of Q occupies 1.4 dm 3 at STP. (P) on reaction with dry ice in dry ether followed by H 3 O + forms a compound (Z). 0.1 mole of (Z) will weigh \ \ \ \ g. (Nearest integer)

Chemistry · Alkyl and Aryl Halides

JEE Main 2026 — 24 January, Evening Shift — Question 71

Grignard reagent $\mathrm{RMgBr}(\mathrm{P})$ reacts with water and forms a gas (Q). One gram of Q occupies $1.4 \mathrm{dm}^{3}$ at STP. (P) on reaction with dry ice in dry ether followed by $\mathrm{H}_{3} \mathrm{O}^{+}$ forms a compound (Z). 0.1 mole of (Z) will weigh $\_\_\_\_$ g. (Nearest integer)

Answer: 6

Numerical answer — enter this value.

Step-by-step solution

$1.4 \mathrm{dm}^{3}$ (or 1.4 mL ) occupied by 1 gm $\therefore$ Molecular weight of $\mathrm{Q}=\frac{22.4}{1.4}=16$ $\therefore \mathrm{Q}$ is $\mathrm{CH}_{4}$ gas and Grignard reagent is $\mathrm{CH}_{3} \mathrm{MgBr}$

\mathrm{CH}_{3} \mathrm{MgBr} \xrightarrow[\text { (ii) } \mathrm{H}_{3} \mathrm{O}^{+}]{\text {(i) } \mathrm{CO}_{2} \text { (dryice) }} \mathrm{CH}_{3} \mathrm{COOH}

(Molecular weight 60) ∴ Weight of 0.1 mole of $\mathrm{CH}_{3} \mathrm{COOH}=6$

Answer key and solution verified before publishing.

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Exam: JEE Main 2026
Paper: 24 January, Evening Shift
Subject: Chemistry
Chapter: Alkyl and Aryl Halides
Topic: Mechanism of Substitution reactions