The dissociation reaction for CH₃COOH in water is written below: CH₃COOH + H₂O ⇌ CH₃COO⁻ + H₃O⁺. Select the ionization constant, Ka, expression for CH₃COOH. 1) Ka = [CH₃COO⁻][H₃O⁺]/[CH₃COOH] 2) Ka = [CH₃COOH]/[CH₃COO⁻][H₃O⁺] 3) Ka = [CH₃COOH][CH₃COO⁻]/[H₃O⁺] 4) Ka = [CH₃COO⁻][H₃O⁺]