Question

10 cbse ncert activity 2.9 solution

Answer 1

1) Dry HCl gas does not turn blue litmus red as aquaous solution of HCl can have H+ ions separated in its solution whereas dry HCl gas does not have separated H+ ions which does not show any acidic nature. This is applicable to all other acids.

2) It turn blue limus red as it has separated H+ ions & has a acidic nature.


Conclusion - A acidic substance show its property of being acidic only if it is has a aquaous solution.

Answer 2

Dry litmus does not show any change, while wet blue litmus turns red bcoz H+ ions are dissociated only in aqueous solutions so H+ cannot be separated from acids in dry conditions.Thus the separation of H+ can only occur in the presence of water .

H+ ions do not exist alone but they with water molecules.