Question

why is dalton's law of partial pressure not applicable to a system of ammonia and hydrogen chloride gas ?

Answer 1

Daltons law of partial pressure is applicable only for a mixture of non reacting substances.

Ammonia and HCl react.Hence,the law is not applicable

Answer 2

Dalton law of partial pressure is applicable only to evaluate a mixture of non- reacting substances.

This should be identified with ammonia and HCL reacts to takes place in applicable law.

Of course, the Daltons law of partial pressure could be measure for a mixture of non reactive gases and denotes reaction between NH3 and HCL occurs is obtained.