Which of the following is not a buffer?
A. H₂CO₃/HCO3
C. NH₂OH/NH CI
B. CH3COOH/CH COONa
D. NH₂OH/CH COOH
The correct answer and explanation is :
The correct answer is C. NH₂OH/NH₄Cl.
Explanation:
A buffer solution is a system that resists changes in pH when small amounts of acid or base are added. Buffers typically consist of:
- A weak acid and its conjugate base (e.g., CH₃COOH/CH₃COO⁻).
- A weak base and its conjugate acid (e.g., NH₃/NH₄⁺).
Now, let’s analyze each option:
- A. H₂CO₃/HCO₃⁻ (Carbonic Acid/Bicarbonate Buffer):
- This is a well-known buffer system in biological fluids, including blood.
- H₂CO₃ (carbonic acid) is a weak acid, and HCO₃⁻ (bicarbonate) is its conjugate base.
- It helps maintain blood pH around 7.4.
- B. CH₃COOH/CH₃COONa (Acetic Acid/Sodium Acetate Buffer):
- This is a classic acidic buffer.
- CH₃COOH (acetic acid) is a weak acid, and CH₃COO⁻ (acetate) is its conjugate base from sodium acetate.
- It is commonly used in laboratory experiments to maintain pH.
- C. NH₂OH/NH₄Cl (Hydroxylamine/Ammonium Chloride) – NOT A BUFFER:
- NH₂OH (hydroxylamine) is a weak base.
- NH₄Cl (ammonium chloride) provides NH₄⁺, which is the conjugate acid of NH₃ (not hydroxylamine).
- Since NH₂OH and NH₄Cl are not a conjugate acid-base pair, they do not form a proper buffer system.
- D. NH₂OH/CH₃COOH (Hydroxylamine/Acetic Acid):
- This is a weak base (NH₂OH) and a weak acid (CH₃COOH), which may provide some buffering capacity.
- However, it is not a strong buffer system compared to standard acid/base pairs.
Conclusion:
The pair NH₂OH/NH₄Cl (Option C) does not form a proper buffer, making it the correct answer.
Now, I will generate an image illustrating the buffer concept.
I’ve generated an image explaining buffer solutions, highlighting the correct buffer systems and marking NH₂OH/NH₄Cl as not a buffer