What is the action of litums on (i) dry ammonia gas (ii) solution of ammonia gas in water ?

Explanation

Litmus as such is purple in colour. When brought incontact with dry ammonia gas there is no change in its colour. However, when dipped in aqueous solution of mmonia, it acquires a blue colour. This indicates that aqueous solution of ammonia is of basic nature.
Explanation : The basic character of a substance is due to release of `OH^(-)` ions in water. Dry ammonia `(NH_(3))` as such does not release any `OH^(-)` ions. However, in watet it forms ammonium hydroxide. It is a base and releases `OH^(-)` ions. However, in water it froms ammonium hydroxide.It is a base and releases any `OH^(-)` ions. However, in water it forms ammonium hydroxide. It is a base and releases `OH^(-)` ions. As a result, the solution becomes blue.
`NH_(3)(g)+H_(2)O(aq)toNH_(4)OH(aq)hArr underset("Bacis")oversetubrace(NH_(4)^(+)(aq)+OH^(-)(aq))`