Answer:
Ammonium chloride
Explanation:
The powder is:- Ammonium chloride
When mixed with silver nitrate, white prescipitate of silver chloride is formed as:-

When mixed with sodium hydroxide, ammonia gas is formed which has noxious order.

Ammonia gas on reaction with nickel (II) hydroxide forms deep blue colored complex as shown below:-
![Ni(OH)_2(s) + 6NH_3(aq)\rightarrow [Ni(NH_3)_6]^{2+}(aq) + 2OH^{-}(aq)](https://tex.z-dn.net/?f=Ni%28OH%29_2%28s%29%20%2B%206NH_3%28aq%29%5Crightarrow%20%5BNi%28NH_3%29_6%5D%5E%7B2%2B%7D%28aq%29%20%2B%202OH%5E%7B-%7D%28aq%29)
Answer : Average atomic weight of copper atoms will be
63.62 u.
Explanation : For calculating average atomic weight for any given atom we use this formula,
m = Σ

X % abundance
where, m - avg atomic mass of isotope.
and

- mass of isotope
on solving we get,
m = [63 u X (69/100)] + [65 u X (31/100)] = 63.62 u.
Answer:
As soon as a front passes a particular location, the weather could change from a steamy maritime tropical air mass to a dry.
Explanation:
hope this helps