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 is a substance that donates a proton (H⁺).
Step 2: Evaluate the options

• Option (1): CH₃NH₃: This is a proton donor, so it is a Bronsted acid.
• Option (2): CH₃COO^-: This is the conjugate base of acetic acid and cannot donate a proton, making it a Bronsted base, not an acid.
• Option (3): H₂O: Water can donate a proton, so it is a Bronsted acid.
• Option (4): HSO₄^-: The hydrogen sulfate ion can donate a proton, making it a Bronsted acid.

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