Final answer:
The conjugate base of CH₃CH₂COOH is CH₃CH₂COO⁻, and the conjugate acid of ClO⁻ is HClO, which corresponds to option A.
Step-by-step explanation:
The conjugate base of CH₃CH₂COOH (propionic acid) is CH₃CH₂COO⁻, and the conjugate acid of ClO⁻ (hypochlorite ion) is HClO (hypochlorous acid). Therefore, the correct answer is A. CH₃CH₂COO⁻, HClO.
When we remove a proton (H+) from an acid, we get its conjugate base. Conversely, when we add a proton to a base, we get its conjugate acid. So for CH₃CH₂COOH, removing an H+ leaves us with CH₃CH₂COO⁻. Similarly, adding an H+ to ClO⁻ yields HClO.