The compound (A) is a white solid. When heated strongly, it leaves no residue. On treating (A) with NaOH solution, a colourless pungent smelling gas (B) is evolved which is industrially highly useful. When the compound (A) is acidified with dilute HCl, a reddish brown gas (C ) is evolved.
The pungent smelling gas (B) is
A. sulphur dioxide
B. chlorine
C. hydrogen chloride gas
D. ammonia.