JEE Chemistry 2026 Question with Solution

Given: The balanced reaction is $2\text{Al} + 6\text{HCl} \rightarrow 3\text{H}_2$.

Find: Which statement about the amount of $\text{H}_2$ produced is correct.

From the balanced chemical equation:

Step 1: Determine mole ratios. From the equation:

Step 2: Convert moles of $\text{H}_2$ to volume at STP. At STP,

Thus,

Therefore, $11.2\text{ L of H}_2\text{ at STP}$ is produced for every mole of HCl consumed. The correct option is A.

Given: Use the balanced equation and STP molar volume.

Find: Which option matches the stoichiometric ratio.

For option A, $1\text{ mol HCl}$ gives $\frac{1}{2}\text{ mol H}_2$, which at STP is $11.2\text{ L}$, so this is correct.

Option B is not supported by the mole ratio and also refers to volume of aqueous HCl, which is not determined from the balanced equation alone.

Option C is incorrect because gas volume depends on temperature and pressure.

Option D is incorrect because from $2\text{ mol Al} \rightarrow 3\text{ mol H}_2$, $1\text{ mol Al} \rightarrow 1.5\text{ mol H}_2$, so at STP the volume is $1.5 \times 22.4 = 33.6\text{ L}$, not $67.2\text{ L}$.

Therefore, the correct option is A.