Apentix/AP Chemistry/Unit 8: Acids and Bases/Question
AP Chemistrymediummcq1 pt

In a solution of diprotic acid H₂A where Ka1 >> Ka2, the [H⁺] is determined mainly by:

A.the second ionization, which releases the remaining proton
B.both ionizations contributing equal amounts of H⁺
C.the first ionization alone, which supplies nearly all the H⁺
D.the autoionization of water

Explanation

Core Concept

When Ka1 dwarfs Ka2 by several orders of magnitude, the first dissociation generates vastly more protons than the second can add. That released H⁺ also suppresses step two through the common-ion effect. Treating such acids as monoprotic with constant Ka1 is therefore an excellent approximation.

Correct Answer

Cthe first ionization alone, which supplies nearly all the H⁺

More Unit 8: Acids and Bases practice questions

Try a random question →

Practice more AP Chemistry questions with full explanations

Practice Unit 8: Acids and Bases Questions →