Answer:
First, precipitate of AgCl is formed. Second, a soluble complex of silver and ammonia is formed. Third, AgCl is reproduced due to disappearance of ammonia complex in presence of 
.
Explanation:
In presence of NaCl, 
forms an insoluble precipitate of AgCl.
Reaction: 
In presence of 
, AgCl gets dissolved into solution due to formation of soluble ![[Ag(NH_{3})_{2}]^{+}](https://tex.z-dn.net/?f=%5BAg%28NH_%7B3%7D%29_%7B2%7D%5D%5E%7B%2B%7D)
complex.
Reaction: ![AgCl(s)+2NH_{3}(aq.)\rightarrow [Ag(NH_{3})_{2}]^{+}(aq.)+ Cl^{-}(aq.)](https://tex.z-dn.net/?f=AgCl%28s%29%2B2NH_%7B3%7D%28aq.%29%5Crightarrow%20%5BAg%28NH_%7B3%7D%29_%7B2%7D%5D%5E%7B%2B%7D%28aq.%29%2B%20Cl%5E%7B-%7D%28aq.%29)
In presence of , complex gets destroyed and free 
again reacts with free 
to produce insoluble AgCl
Reaction: ![[Ag(NH_{3})_{2}]^{+}(aq.)+2H^{+}(aq.)+Cl^{-}(aq.)\rightarrow AgCl(s)+2NH_{4}^{+}(aq.)](https://tex.z-dn.net/?f=%5BAg%28NH_%7B3%7D%29_%7B2%7D%5D%5E%7B%2B%7D%28aq.%29%2B2H%5E%7B%2B%7D%28aq.%29%2BCl%5E%7B-%7D%28aq.%29%5Crightarrow%20AgCl%28s%29%2B2NH_%7B4%7D%5E%7B%2B%7D%28aq.%29)
3Fe(s) + 4H2O(l) — 1Fe3O4(s) + 4H2(g)
None of above. only temperature stays constant.
Symbol: Hg
Made of hydrargyrum
Atomic number: 80
Atomic weight: 200.59
Poor conductor if heat and an ok conductor for electricity. Primarily used for many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents.
Hope it helps!
Go here and see how:
http://www.rsc.org/learn-chemistry/resource/res00000698/using-indigestion-tablets-to-neutralise-an-acid?cmpid=CMP00005978
