Question

explain the buffer action of a basic buffer solution of ammonium hydroxide and ammonium chloride

Answer 1

A solution which resist the change in its pH value, on adding  

small amount of strong acid or base.

The pH value of a buffer does not change on dilution.  This property of resisting the change in pH value is called as Buffer solution

Buffer action of a basic buffer solution of ammonium hydroxide and ammonium chloride:

NH₄OH(aq)⇔ NH₄⁺(aq) +OH⁻(aq)---- partial ionisation

NH₄Cl(aq) -->NH₄⁺ (aq)  + Cl⁻(aq)---- complete ionisation

If strong acid like HCl is added in smalll quantity to buffer solution,  

so the extra H+ ions of acid combines with NH₄OH to produce ammonium ions and water

HCl (aq)+NH₄OH(aq)--->NH4Cl(aq) +H2O(aq)

H+ (aq)+ NH4OH (a)--->NH₄⁺ +H2O

since additional of H+ions of acid are neutralized, so the pH pf solution remains same