Question

Which equation represents the reaction of acetic (ethanoic) acid with water?

CH3COO- + H2O CH3COOH + OH-

CH3COOH + H2O CH3COO- + H3O+

CH3COO- + H2O CH3COO2- + H3O+

CH3COOH + H2O CH3COOH2+ + OH-

Answer 1

First you have to know what is acetic acid, do you know what that is?
It's alright if you don't know, I'll explain it to you :)

Answer 2

Why do they need to know what acetic acid is? The condensed formula is already given and they are all correct.
They just need to be able to recognize that this is an acid-base reaction and identify the conjugate acid/base.

Answer 3

Ethanoic acid is a monoprotic (donating only one proton) acid with the formula: CH3COOH.
In water it dissociates:
CH3COOH + H2O = CH3COO- + H3O+

Answer 4

\[CH _{3}COOH + H _{2}O \rightarrow CH _{3}COO ^{-} + H _{3}O ^{+}\]