Answer:
Ammonium chloride
Explanation:
The powder is:- Ammonium chloride
When mixed with silver nitrate, white prescipitate of silver chloride is formed as:-
[tex]NH_4Cl+AgNO_3\rightarrow NH_4NO_3+AgCl[/tex]
When mixed with sodium hydroxide, ammonia gas is formed which has noxious order.
[tex]NH_4Cl +NaOH\rightarrow NH_3 + H_2O + NaCl[/tex]
Ammonia gas on reaction with nickel (II) hydroxide forms deep blue colored complex as shown below:-
[tex]Ni(OH)_2(s) + 6NH_3(aq)\rightarrow [Ni(NH_3)_6]^{2+}(aq) + 2OH^{-}(aq)[/tex]