What colour change does a blue or red litmus paper exhibit when it is put separately in each of the following aqueous solutions ?
`CH_(3)COONH_(4)`.

Explanation

In its aqueous solution, `CH_(3)COONH_(4)` dissociates completely forming `NH_(4)^(+)(aq) and CH_(3)COO^(-)(aq)` ions. Both these ions undergo hydrolysis in water. The important fact is that in water the strength of `CH_(3)COO^(-)` ion as a base and the strength of `NH_(4)^(+)` ion as an acid are the same. consequently, the concentration of `OH^(-)` ions produced due to hydrolysis of `CH_(3)COO^(-)` ions:
`[CH_(3) COO^(-)(aq)+H_(2)O(l)hArr CH_(3)COOH(aq)OH^(-)(aq)]`
is almost the same as the concentration of `H_(3)O^(+)` ions produced due to hydrolysis of `NH_(4)^(+)` ions:
`[NH_(4)^(+)(aq)+H_(2)O(l)hArr NH_(3)(aq)+H_(3)O^(+)(aq)]`
as a result, an aqueous solution of `CH_(3)COONH_(4)` is neutral. so, if a litmus paper is dipped into this solution, it will not exhibit any colour charge.