F4/5 Chem: ammonium compund

Both equations are correct, and both reaction occurs in suitable conditions.
Now, you are going to test for ammonium compound, but NOT ammonia gas. The second method is a better one to test for ammonium compound.
For the second method, only NH3 is evolved. You can simply test NH3 gas by a piece of moist red litmus paper, which is changed to blue by NH3 gas.
For the first method, other gasesous product may also be formed depending what ammonium compound is used. The case may be complicated is complicated. For example, when NH4Cl is heat, NH3 gas and HCl gas are formed. NH3 gas can change moist red litmus paper to blue, but HCl gas can change moist blue litmus paper to red. Therefore, it is difficult to show the presence of ammonia.

Both equations are correct.
Also, both are can test the presence of ammonia gas.
However, i will prefer the second one which is adding alkali before heating.
The products are salt and water which is non-toxic.

If you heat NH4Cl alone, toxic HCl gas will be evolved.

2008-04-08 09:21:30 補充：
Oh.

actually, the prsence of NH3 gas is a test of ammonium compound, isn't it??
or can you identify an ammonium compound without testing ammonia gas alone??