Which solution is a buffer? A)a solution that is 0.200 M in H₃PO₄ and 0.200 M in HBr B)a solution that is 0.200 M in H₃PO₄ and 0.200 M in Na₂HPO₄ C)a solution that is 0.200 M in H₃PO₄ and 0.200 M in NaBr D)a solution that is 0.200 M in H₂SO₄ and 0.200 M in Na₂SO₄

Question

Quizplus · Accepted Answer

A buffer is a solution that can resist a change in pH when small amounts of acid or base are added to it. It contains both a weak acid and its conjugate base (or a weak base and its conjugate acid) in roughly equal quantities. In option B, the presence of H₃PO₄ (which is a weak acid) and Na₂HPO₄ (which is its conjugate base) in equal concentrations makes it a buffer. Option A has no conjugate base, option C has a strong acid (HBr), and option D has two strong electrolytes.

Which Solution Is a Buffer