What volume of hydrogen gas at STP would be liberated by action of 50 mL of H 2 SO 4 of 50 \% purity (density =1.3 g mL -1 ) on 20 g of zinc? Given : Molar mass of H, O, S, Zn are 1, 16, 32, 65 g mol -1 respectively.

Chemistry · Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry

JEE Main 2026 — 5 April, Evening Shift — Question 49

What volume of hydrogen gas at STP would be liberated by action of 50 mL of $\mathrm{H}_{2} \mathrm{SO}_{4}$ of $50 \%$ purity (density $=1.3 \mathrm{~g} \mathrm{~mL}^{-1}$ ) on 20 g of zinc?

Given : Molar mass of H, O, S, Zn are 1, 16, 32, 65 $\mathrm{g} \mathrm{mol}^{-1}$ respectively.

Option A:
5.824 L
Option B:
7.428 L
Option C:
6.892 L
Correct
Option D:
8.375 L

Answer: C

Step-by-step solution

Mass of $\mathrm{H}_{2} \mathrm{SO}_{4}=\frac{50 \times 1.3}{98} \times \frac{50}{100}=\frac{32.5}{98}$ $\mathrm{Zn}(\mathrm{s})+\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) \rightarrow \mathrm{ZnSO}_{4}(\mathrm{aq})+.\mathrm{H}_{2}(\mathrm{~g})$ $\frac{20}{65} \quad \frac{32.5}{98}$ Moles of $\mathrm{H}_{2}$ formed $=\frac{20}{65}$ Volume of $\mathrm{H}_{2}=\frac{20}{65} \times 22.7=6.9 \mathrm{~L}$ .

Answer key and solution verified before publishing.

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Exam: JEE Main 2026
Paper: 5 April, Evening Shift
Subject: Chemistry
Chapter: Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry
Topic: Chemical Equations, Stoichiometry and Limiting Reagent