Question

an aqua solution turns red litmus solution blue.addition of excess of which of the following solution
would reverse the change?
(a) Baking soda
(b) Lime water
(c) Ammonium hydroxide solution
(d)hydrochloric acid

Answer 1

since the aqueous solution turns red litmus blue
hence , the solution is basic in nature

therefore , addition of excess of d) hydrochloric acid would reverse the change

the change would be that it will not have any effect on red litmus paper , but turn blue litmus paper red
hope this helps

Answer 2

that will be hydrochloric acid