Question

In each of the following questions, an Assertion (A) is followed by a corresponding Reason (R). Use the following keys to choose the appropriate answer.

Assertion (A): If 30 mL of $H_2$ and 20 mL of $O_2$ react to form water, 5 mL of $H_2$ is left at the end of the reaction.
Reason (R): $H_2$ is the limiting reagent.

• A. If both (A) and (R) are correct and (R) is the correct explanation for (A).
• B. If both (A) and (R) are correct and (R) is not the correct explanation for (A).
• C. If (A) is correct but (R) is incorrect.
• D. If (A) is incorrect and (R) is correct.
• E. If both (A) and (R) are incorrect.

Answer 1

The correct option is D

If (A) is incorrect and (R) is correct.

(A) is wrong, but (R) is correct.
$\underset{30mL}{H_2}+\underset{15mLreacted}{\frac{1}{2}{O}_2}\to H_{2}O$
Volume of $O_2$ left = 20 - 15 = 5 mL
(R) is correct, since $H_2$ is completely consumed, and hence is the limiting reagent.