Question

What is more acidic from [CuCl4]^(-2) and ethanoic acid? And what is the reason?

Answer 1

My gut feeling is the acetic acid is more acidic but I couldn't prove that.

Answer 2

Would [CuCl4]^(-2) be hydrolyzed? :
Cl- <===> HCl + OH-

But Cl^(-) is a strong acid anion..

Answer 3

Cl^- is such a weak base that it does not hydrolyze. Think NaCl in aqueous solution. Neither Na^+ nor Cl^- hydrolyzes so NaCl solutions are neutral. That's unlike NH4Cl where the NH4^+ hydrolyzes (Cl^- does not) to make an acidic solution or sodium acetate (NaAc) where the Ac^- hydrolyzes (Na^+ does not) to make a basic solution. Your last sentence says it all; i.e., Cl^- is a strong acid anion. Therefore, it MUST be a weak base. It can't pull that H^+ away from HOH.

Answer 4

Thank you for the explanation!