Final answer:
CHO₂⁻ is a weak base, while ClO₄⁻ is pH-neutral.
Formate ion (CHO₂⁻) is a weak base as its corresponding acid, formic acid, is a weak acid. Perchlorate ion (ClO₄⁻) is pH-neutral because its corresponding acid, perchloric acid, is a strong acid. Therefore, the anions are classified accordingly.
Step-by-step explanation:
(a) CHO₂⁻ is a weak base. Anions of weak acids are typically weak bases.
(b) ClO₄⁻ is pH-neutral. Perchlorate anion does not have any basic or acidic properties.
Formate ion (CHO₂⁻) is a weak base as its corresponding acid, formic acid, is a weak acid. Perchlorate ion (ClO₄⁻) is pH-neutral because its corresponding acid, perchloric acid, is a strong acid. Therefore, the anions are classified accordingly.
To classify each anion, we must consider the nature of its corresponding acid. Anions derived from a strong acid tend not to react with water, making them pH-neutral, while anions derived from weak acids can act as weak bases when they react with water to form OH- ions.
Classification:
(a) CHO₂⁻ (formate ion): The corresponding acid of CHO₂⁻ is formic acid, which is a weak acid. Therefore, formate is a weak base as it can accept protons from water, increasing the OH- concentration in solution.
(b) ClO₄⁻ (perchlorate ion): The corresponding acid of ClO₄⁻ is perchloric acid, which is one of the strongest acids known. Consequently, ClO₄⁻ is pH-neutral, as it does not react significantly with water.