Question

An aqueous solution turns red litmus solution blue. Excess addition of which solution would reverse the change- ammonium hydroxide solution or hydrochloric acid?

Answer 1

Since the red litmus turned blue, this means that the tested aqueous solution is basic in nature. So as to reverse the colour of the litmus, we need to change the nature of the solution (from basic to acidic), for which we have to add an acid to first neutralise the base and then more to make the make the solution acidic in nature.

Ammonium hydroxide is a base and thus would not give the desired results. 
For this, you would need hydrochloric acid (HCl) because it's acidic in nature.

Answer 2

Answer:

HCL is the correct answer!!!!!