Q. Which of the following pairs constitutes a buffer ?
A) HNO₂ and NaNO₂
B) NaOH and NaCl
C) HNO₃ and NH₄NO₃
D) HCl and KCl
Explanation
[Solution from source] A buffer needs a weak acid with its conjugate base (or weak base with its conjugate acid). HNO₂ is a weak acid and NaNO₂ supplies NO₂⁻, so this pair is an acidic buffer. The other pairs contain a strong acid or strong base with a neutral salt and cannot resist pH changes. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.