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

Explanation

In its aqueous solution, `NH_(4)Cl` dissociates completely forming `NH_(4)^(+)(aq) and Cl^(-)(aq)`. `NH_(4)^(+)` ions so formed undergo hydrolysis, and thereby increase the concentration of `H_(3)O^(+)` ions in the solution as a result, as aqueous solution of `NH_(4)Cl` is acidic. therefore, if a blue litmus paperr is dipped into this solution, its colour will change to red.