I just wanted to make sure that this wording makes sense.

Question

What chemical equation represents the ability of a substance to donate a proton in water?

A. NH3 + H2O <-> NH4+ + OH-
B. CH3COOH + NaOH <-> CH3COOH + NaCl
C. CH4 + 2O2 -> CO2 + H2O
D. CH3COOH + H2O <-> CH3COO- + H3O+

I'm thinking it's A, as when ammonia is in water, water will donate a proton while ammonia accepts. However due to the wording, I think the question is asking for vice versa, where water acts as the base and the other substance acts as an acid so then it would be D, as
CH3COOH acts as the acid and H2O acts as the base.

I believe I'm overthinking this problem, however I would like someone to check my answer as I would rather be safe than sorry.

Thank you in advance.

- Sydney

Answer 1

A is correct.

Answer 2

I don't interpret the question that way. It is asking, in my opinion, for the equation in which a substance (NH3 in a, CH3COOH in b, CH4 in c, CH3COOH in d) donates a proton when in water solution. It is true in a that H2O is donating a proton to NH3 which make NH3 a base and H2O an acid but I don't think the question is about H2O; i. e., only that the substance (NH3) is in solution and it happens to be H2O. I think the correct answer is d. It is clear in d that CH3COOH (the substance other than H2O) is donating a proton to H2O to form the H3O^+. By the way, answer b makes no sense (how did we get NaCl in the picture) and answer c isn't balanced.