But, if you have problems to purchase Ammonia, a water solution of NH3, let us use Ammonium Sulfate that is sold as fertilizer in all agriculture drugstore and the equation:
2NaOH + (NH4)2SO4 ---> Na2SO4 + 2NH3 + 2H2O
You will end with a mixture of Sodium sulfate and Ammonia. If you search the properties of Sodium Sulfate at Wikipedia, you will find this curve:
|Solubility of Sodium Sulfate in water|
Dissolve 132 g of Ammonium Sulfate in some 250 ml water in a 1 liter beaker. Do the same with 80 g Sodium Hydroxide in a smaller beaker. Pour the solution of Sodium Hydroxide to the solution of Ammonium Sulfate and mix until most of the stoichiometric reaction take place. Let cool and put in your refrigerator. Next morning you will have the bottom full of precipitate, Sodium Sulfate. Just decant to another bottle and yo will have produced Ammonia, perhaps some 10% solution of Ammonia that you can use as fixer in Photography. The smell of this weak solution is tolerable. It works fine, already tested. And it may be reused, I think, until exhaustion.
Important notice about ammonia as fixer:
I found this in the Wikipedia:
« silver chloride (AgCl) is soluble in dilute (2M) ammonia solution, silver bromide (AgBr) is only soluble in concentrated ammonia solution, whereas silver iodide (AgI) is insoluble in aqueous ammonia.»
After fixing a piece of film with ammonia I am going to make the sulfide test.