Question

briefly explain why the solution of ammonium chloride turns litmus paper

Answer 1

Ammonium Chloride NH₄Cl is mostly acidic in nature. Hence, on pouring it on a red litmus paper will show no changes.

But, it will turn a blue litmus paper/solution to red due to it being slight acidic ranging from 4.6 to 6.0 (this varies of the concentration of the NH₄Cl provided).