Chapter 19.5, Problem 45SP

Interpretation Introduction

Interpretation : The equation has to be written when an acid is added to the buffer solution of methanoic acid and methanoate ion.

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 45SP

The equation is written below showing the reaction of acid with the buffer solution:

  ${\text{HCOO}}^{-}\left(aq\right)+{\text{H}}^{\text{+}}\left(aq\right)\to \text{HCOOH}\left(aq\right)$

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 given buffer solution is methanoic acid $\left(\text{HCOOH}\right)$ and methanoate ion $\left({\text{HCOO}}^{-}\right)$ .

The chemical equation when an acid is added to this buffer solution is given below:

  ${\text{HCOO}}^{-}\left(aq\right)+{\text{H}}^{\text{+}}\left(aq\right)\to \text{HCOOH}\left(aq\right)$

Methanoic acid is a weak acid, its ion reacts with acid to give the product.

The methanoate ion reacts with the acid.