Which of the following anions act as weak bases in solution?

ClO4-
ClO-
C2H3O2-
Cl-

I think its ClO4- and Cl-

Ah, I see you're having an "anion conundrum!" Allow me to clarify, my friend. While both ClO4- and Cl- might make you think they have a weak base potential, they're actually quite the "chlorine-y duo" when it comes to weak bases. ClO4- is too stable to act as a weak base, and Cl- is just plain old "salty" and not basic at all. So, the true weak base in this bunch is C2H3O2-, because it's not as "ace-tastic" at stabilizing itself.

The anions that act as weak bases in solution are ClO- (hypochlorite ion) and C2H3O2- (acetate ion).

ClO4- (perchlorate ion) and Cl- (chloride ion) are not considered weak bases because they do not accept protons (H+ ions) from water to a significant extent.

To determine which anions act as weak bases in solution, we need to consider their conjugate acids. Anions that are the conjugate bases of weak acids tend to act as weak bases.

To identify the conjugate acid of each anion, we need to know the corresponding acid-base reaction. Let's examine each anion and its conjugate acid:

1. ClO4- (perchlorate ion): The conjugate acid is HClO4 (perchloric acid).
- HClO4 is a strong acid, so its conjugate base (ClO4-) is a very weak base.
- Therefore, ClO4- does not act as a weak base in solution.

2. ClO- (hypochlorite ion): The conjugate acid is HOCl (hypochlorous acid).
- HOCl is a weak acid, so its conjugate base (ClO-) is a weak base.
- Therefore, ClO- can act as a weak base in solution.

3. C2H3O2- (acetate ion): The conjugate acid is CH3COOH (acetic acid).
- CH3COOH is a weak acid, so its conjugate base (C2H3O2-) is a weak base.
- Therefore, C2H3O2- can act as a weak base in solution.

4. Cl- (chloride ion): The conjugate acid is HCl (hydrochloric acid).
- HCl is a strong acid, so its conjugate base (Cl-) is a very weak base.
- Therefore, Cl- does not act as a weak base in solution.

Based on the analysis above, the anions ClO- (hypochlorite ion) and C2H3O2- (acetate ion) act as weak bases in solution.

HClO_4 and HCl are strong acids

all of those with an -OH would be weak bases

Strong bases:
LiOH, NaOH, KOH, Ca(OH)_2, Sr(OH)_2, Ba(OH)_2