Question

A sample of solid ammonia chloride NH4Cl, is dissolved in water...the solution found is acidic...explain why the solution is acidic?

Answer 1

Note the correct name is ammonium chloride. It is acid because the ammonium ion (the NH4^+) is hydrolyzed as follows:
NH4^+ + H2O ==> H3O^+ + NH3
The hydronium ion makes it acidic.