Chapter 14.9, Problem 14.72QAP

Interpretation Introduction

Interpretation: Consider the buffer system of nitrous acid, HNO₂, and its salt, NaNO₂

a. The purpose of this buffer system is to:

1. Maintain [HNO₂]

2. Maintain [NO₂^-]

3. Maintain pH

b. The weak acid is needed to

1. Provide the conjugate base

2. Neutralize added OH^-

3. Provide the conjugate acid

c. If H₃O⁺ is added, it is neutralised by

1. The salt

2. H₂O

3. H₃O⁺

d. When OH^- is added, the equilibrium shift in direction of the:

1. Reactants

2. Product

3. Does not change

Concept introduction:

A buffer system is a solution that resists change in pH when acids or bases are added to it.

Buffer systems are made of either a weak acid and its salt or a weak base and its salt.