Question

Which of the following is not a Bronsted acid?

• A. CH₃NH₃ (Methylammonium ion)
• B. CH₃COO^- (Acetate ion)
• C. H₂O (Water)
• D. HSO₄^- (Hydrogen sulfate ion)

Hint:

Bronsted acids are proton donors, while Bronsted bases are proton acceptors.

Answer 1

The Correct Option is B

Step 1: Bronsted Acid: Definition
A Bronsted acid releases a proton (H⁺).
Step 2: Analysis of Choices

• Choice (1): CH₃NH₃: This compound donates a proton, therefore it's a Bronsted acid.
• Choice (2): CH₃COO^-: This is the conjugate base of acetic acid and cannot release a proton. It functions as a Bronsted base, not an acid.
• Choice (3): H₂O: Water can donate a proton, thus it's a Bronsted acid.
• Choice (4): HSO₄^-: The hydrogen sulfate ion can donate a proton, identifying it as a Bronsted acid.

Step 3: Summary
The acetate ion, CH₃COO^-, is not a Bronsted acid. It is a base that accepts a proton.