Chapter 19, Problem 78A

Interpretation Introduction

Interpretation : A buffered solution cannot absorb an unlimited amount of acid or base to be explained.

Concept Introduction : A buffer is a solution that retains the pH of a solution irrespective of the addition of small amounts of acids or bases.

Answer to Problem 78A

Due to buffer capacity, the buffered solution cannot absorb an unlimited amount of acid or base.

Explanation of Solution

A weak acid and one of its salts or a weak base and one of its salts are solutions that are used as buffers.

Buffers are formed by the combination of weak acids or bases with their respective salts.

The volume of acid or base that can be supplied to a buffer solution without causing a pH shift is known as the buffer capacity.

A buffered solution cannot absorb an unlimited amount of acid or base.

This is true because a buffered solution will eventually reach its buffer capacity, at which time it will no longer be able to take in ${\text{H}}^{\text{+}}$ ions (remember that ${\text{A}}^{-}$ ions absorb hydrogen ions) or ${\text{OH}}^{-}$ ions (remember that HA (acid) reacts with ${\text{OH}}^{-}$ ).