Question

Given the equation representing a reversible reaction:which formula represents the h+ acceptor in the forward reaction?

Answer 1

Question is incomplete. Complete question is attached below
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Answer: Option A: HCO3-(aq.)

Reason:
From the reaction, it can be seen that following reaction occurs in forward direct

HCO3-(aq) + H2O(l) → H2CO3(aq) + OH-(aq)

In above forward reaction, HCO3- accepts proton from H2O to generate H2CO3. Thus, according to Lowry and Bronsted theory of acid-base, HCO3- is a base, while H2CO3 is a conjugate acid.