# Answer the following : A solution of CH3COONH4 is neutral. why? - Chemistry

A solution of CH3COONH4 is neutral. why?

#### Solution

i. CH3COONH4 is a salt of a weak acid, CH3COOH (Ka = 1.8 × 10–5), and weak base, NH4OH (Kb = 1.8 × 10–5). When the salt CH3COONH4 is dissolved in water, it undergoes hydrolysis:

$\ce{CH3COO^-_{ (aq)} + NH^+_{ 4(aq)} + H2O_{(l)} ⇌ \underset{\text{(weak acid)}}{CH_3COOH_{(aq)}} + \underset{\text{(weak base)}}{NH4OH_{(aq)}}}$

ii. The ions of the salt react with water as

$\ce{CH3COO^-_{ (aq)} + H2O_{(l)} ⇌ CH3COOH_{(aq)} + OH^-_{ (aq)}}$  ...(1)

$\ce{NH^4+_{ (aq)} + 2H2O_{(l)} ⇌ NH4OH_{(aq)} + H3O^+_{ (aq)}}$ ...(2)

iii. As Ka = Kb, the relative strength of acid and base produced in hydrolysis is the same.

iv. Therefore, the solution is neutral. Hydrolysis of " NH"_4^+ produces as many H3O+ ions as that of CH3COO produces OH ions.

Concept: Hydrolysis of Salts
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#### APPEARS IN

Balbharati Chemistry 12th Standard HSC for Maharashtra State Board
Chapter 3 Ionic Equilibria
Exercises | Q 4.03 | Page 62