Which combination of solutions is the best choice for making a buffer solution?
A) equal volumes of 1 M acetic acid and 0.005 M sodium acetate
B) equal volumes of 0.5 M nitric acid and 0.5 M sodium hydroxide
C) equal volumes of 0.1 M formic acid and 0.1 M sodium formate
D) equal volumes of 0.1 M sulfuric acid and 0.001 M sodium sulfate
E) equal volumes of 0.05 M hydrochloric acid and 0.075 ammonium chloride

Question

Quizplus · Accepted Answer

A buffer solution is made of a weak acid and its conjugate base, or a weak base and its conjugate acid. Option C is the best choice because it contains a weak acid (formic acid) and its conjugate base (sodium formate) at the same concentrations. Options A, B, and D do not involve a weak acid or its conjugate base, and option E involves a strong acid (hydrochloric acid) and a weak base (ammonium chloride), which can result in a less effective buffer.

Which Combination of Solutions Is the Best Choice for Making