If the acid base reaction HA(aq)+B^-(aq)---> HB(aq)+A^-(aq)

Question

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has a k = 10^-4,which of the following statements are true & why?
(a)HB is a stronger acid than HA
(b)HA is a stronger acid than HB
(c)HA & HB have same acidity
(d)B^- is a stronger base than A^-
(e)A^- is a stronger base than B^-
(f)B^-and HB are conjugate acid-base pair
(g)the acid & base strength can cannot be compared

Answer 1

In a Bronsted-Lowry acid-base reaction with a high Keq value,
Acid + Base = Weaker acid + Weaker Base
Acid1 + Base1 = Base2 + Acisd2
Acid1 is stronger than Acid2, and,
Base1 is stronger than Base2
In your question, the equilibrium constant is small. The forward (left to right) reaction does not go far. We can assume the the acid and the base on the right side are stronger than the acid and the base on the left.
Based on the above discussion, (a) is a correct statement. I will let you decide on the others.