Answer:
a. CH3COO⁻.
Step-by-step explanation:
Hello there!
In this case, according to the given ionization reaction of acetic acid:
CH₃COOH + H₂O --> H₃O⁺ + CH₃COO⁻
Whereas we can evidence how the CH₃COOH is the acid whereas H₂O the base, as the former donates H ions to the latter, which accepts them; we can infer that H₃O⁺ is the conjugate acid, resulting from the base and the a. CH3COO⁻ is the conjugate base, resulting from the acid.
Best regards!