Chem 14B Lecture 5 Acids and Bases

[nithika karthikeyan 3H]

During Lecture 5, the professor said that CH3COOH acts as a base in the reaction: CH3COOH + H2O --> H3O+ + CH3COO-. Why is this?

[George_Furey_1C]

I didn't catch him say this but that's weird if he did because acetic acid is a known weak acid that donates a proton. Is it possible he was referring to CH3COO- as the conjugate base? In this reaction water is acting as the base by accepting the proton and becoming H3O+.

[graceswenson3a]

I believe CH3COO-, the conjugate base, is used as a base in another reaction, which Dr. Lavelle may have referred to:

CH3COO-(aq) + H2O(l) --> CH3COOH(aq) + OH-(aq)

Regardless, CH3COOH in the original reaction acts as an acid, and in the subsequent reaction CH3COOH is a conjugate acid. Hope this helps.