Solve this reaction scheme given.?

Question

White crystalline salt "P" --->warm aqueous sodium hydroxide ---> gas "Q" ---> moist red litmus ---> blue.
White crystalline salt "P" ---> aqueous salt ---> dilute nitric acid with aqueous silver nitrate ---> to produce white precipitate "R".

Name the substance "P", "Q" & "R".
Solve this question correct with detailed workings and earn points!!! :)

Answer 1

I think it is

P = ammonium chloride NH4Cl
Q = ammonia NH3
R = Silver Chloride AgCl

The ammonium chloride will react with NaOH releasing ammonia. It will turn red litmus to blue

The silver will react with the chloride and precipitate