Correct: ammonium salts on heating decompose to give ammonia

Dear student,

Yes, we can obtain NH₃ on the decomposition of ammonium salts
for eg.
NH₄Cl ----> NH₃+HCl
But that's also true not all ammonium salts decompose to give ammonia gas, eg. NH₄NO₃.

In nutshell,  ammonium salts on heating decompose to give ammonia but not every time (exceptions exists)

Regards