In aqueous solution, the ionization constants for carbonic …

Chemistry Ionic Equilibrium JEE Advanced Previous Years Question Single Correct MCQ

Published on: August 13, 2026

In aqueous solution, the ionization constants for carbonic acid are

K 1 = 4.2 × 10 –7 and K 2 = 4.8 × 10 –11 Select the correct statement for a saturated 0.034 M solution of the carbonic acid.

The concentration of CO 3 2– is 0.034 M.

The concentration of CO 3 2– is greater than that of HCO 3 – .

The concentration of H + and HCO 3 – are approximately equal.

The concentration of H + is double that of CO 3 2– .

Text Solution

Verified by Experts

The correct answer is:

and are incorrect since H 2 CO 3 is not a strong acid.

H 2 CO 3 H + + HCO 3 – K 1 = 4.2 × 10 –7

HCO 3 – H + + CO 3 2– K 2 = 4.8 × 10 –11

 K 1 >> K 2 , so H + produced from II nd ionisation can be neglected as compared to those produced in I st ionisaiton.

∴ [H + ] = [HCO 3 – ] (from I st ionisation)

Also, [CO 3 2– ] << [HCO 3 – ] (  II nd ionisation will occur upto negligible extent).

Previous Question Next Question

Get practice questions, solutions, and test series in one place.

Share your experience with this question and solution.

Send your comment, doubt, correction, or feedback to admin.

What students say about this solution

No reviews yet. Be the first to write a review.