JEE Main 2026 — Chemistry Physical Chemistry

2026mcqmedium

In the reaction,

$2 \mathrm{Al}(\mathrm{s})+6 \mathrm{HCl}(\mathrm{aq}) \rightarrow 2 \mathrm{Al}^{3+}(\mathrm{aq})+6 \mathrm{Cl}^{-}(\mathrm{aq})+3 \mathrm{H}_{2}(\mathrm{~g})$

Official previous-year question

Held on 22 Jan 2026 · Verified 6 Jul 2026.

Options

A
$11.2 \mathrm{~L} \mathrm{H}_{2}(\mathrm{~g})$ at STP is produced for every mole of HCl consumed.
B
$33.6 \mathrm{~L} \mathrm{H}_{2}(\mathrm{~g})$ is produced regardless of temperature and pressure for every mole of Al that reacts.
C
$12 \mathrm{~L} \mathrm{HCl}(\mathrm{aq})$ is consumed for every $6 \mathrm{~L} \mathrm{H}_{2}(\mathrm{~g})$ produced.
D
$67.2 \mathrm{~L} \mathrm{H}_{2}(\mathrm{~g})$ at STP is produced for every mole of Al that reacts.

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Solution

Reaction: $2\text{Al}(s) + 6\text{HCl}(aq) \rightarrow 2\text{Al}^{3+}(aq) + 6\text{Cl}^-(aq) + 3\text{H}_2(g)$

Checking each option:

(1) Per 1 mole HCl: From stoichiometry, 6 mol HCl produces 3 mol H₂, so 1 mol HCl produces 0.5 mol H₂ = 11.2 L at STP. TRUE

(2) Per 1 mole Al: 2 mol Al produces 3 mol H₂, so 1 mol Al produces 1.5 mol H₂ = 33.6 L at STP only, not regardless of T and P. FALSE

(3) Volume ratio at same T,P: 6 mol HCl : 3 mol H₂ = 2:1, so 12 L HCl : 6 L H₂. TRUE

(4) Per 1 mole Al: 1.5 mol H₂ = 33.6 L, not 67.2 L. FALSE

Option (1) is correct.

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Options

$11.2 \mathrm{~L} \mathrm{H}_{2}(\mathrm{~g})$ at STP is produced for every mole of HCl consumed.

$33.6 \mathrm{~L} \mathrm{H}_{2}(\mathrm{~g})$ is produced regardless of temperature and pressure for every mole of Al that reacts.

$12 \mathrm{~L} \mathrm{HCl}(\mathrm{aq})$ is consumed for every $6 \mathrm{~L} \mathrm{H}_{2}(\mathrm{~g})$ produced.

$67.2 \mathrm{~L} \mathrm{H}_{2}(\mathrm{~g})$ at STP is produced for every mole of Al that reacts.

Solution

Reaction: $2\text{Al}(s) + 6\text{HCl}(aq) \rightarrow 2\text{Al}^{3+}(aq) + 6\text{Cl}^-(aq) + 3\text{H}_2(g)$

Checking each option:

(1) Per 1 mole HCl: From stoichiometry, 6 mol HCl produces 3 mol H₂, so 1 mol HCl produces 0.5 mol H₂ = 11.2 L at STP. TRUE

(2) Per 1 mole Al: 2 mol Al produces 3 mol H₂, so 1 mol Al produces 1.5 mol H₂ = 33.6 L at STP only, not regardless of T and P. FALSE

(3) Volume ratio at same T,P: 6 mol HCl : 3 mol H₂ = 2:1, so 12 L HCl : 6 L H₂. TRUE

(4) Per 1 mole Al: 1.5 mol H₂ = 33.6 L, not 67.2 L. FALSE

Option (1) is correct.

JEE Main 2026 — Chemistry Physical Chemistry

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JEE Main 2026 — Chemistry Physical Chemistry

Options

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry