Question

Assertion (A): Dilute Sulphuric acid is a stronger electrolyte than concentrated Sulphuric acid.
Reason (R): Dilute Sulphuric acid has a higher concentration of mobile ions than concentrated Sulphuric acid.

• A. (A) is true but (R) is false.
• B. (A) is false but (R) is true.
• C. Both (A) and (R) are true and (R) is the correct explanation of (A).
• D. Both (A) and (R) are true, but (R) is not the correct explanation of (A).

Hint:

Pure 100% sulphuric acid is a poor conductor because it contains almost no ions. It’s the water that "unlocks" the ions through the process of electrolytic dissociation!

Answer 1

The Correct Option is C

To address this question, we need to evaluate the assertion and the reason separately, and then decide if the reason is the correct explanation for the assertion.

Assertion (A): Dilute Sulphuric acid is a stronger electrolyte than concentrated Sulphuric acid.

An electrolyte's strength is determined by its ability to dissociate into ions in solution. Dilute sulphuric acid contains more water, which facilitates the dissociation of sulphuric acid into its ions \((\text{H}^+ \text{ and } \text{SO}_4^{2-})\). Therefore, dilute sulphuric acid, having more mobile ions, acts as a stronger electrolyte.

Reason (R): Dilute Sulphuric acid has a higher concentration of mobile ions than concentrated Sulphuric acid.

This reason is valid because, in dilute solutions, the dissociation of sulphuric acid is more complete due to the availability of water molecules. As a result, the concentration of mobile ions is higher compared to concentrated sulphuric acid, where ion-pair formation or incomplete dissociation might occur due to less availability of water.

Conclusion: Both the assertion and the reason are true, and the reason correctly explains the assertion. Thus, the correct answer is that both (A) and (R) are true, and (R) is the correct explanation of (A).