"PARAGRAPH II"

A trinitro compound, 1, 3,5 tris-(4-nitrophenyl) benzene, on complete reaction with an excess of Sn/HCl gives major product, which on treatment with an excess of NaNO 2 /HCl at 0°C provides P as the product. P, upon treatment with excess of H 2 O at room temperature, gives the product Q. Bromination of Q in aqueous medium furnishes the product R. The compound P upon treatment with an excess of phenol under basic conditions gives the product S.

The molar mass difference between compounds Q and R is 474 mol -1 and between compounds P and Sis 172.5 gmol -1 .

The total number of carbon atoms and heteroatoms present in one molecule of S is_____. [Use: Molar mass in g mol -1 ]: H = 1, C = 12, N = 14, O = 16, Br = 80, Cl = 35.5 Atoms other than C and H are considered as heteroatoms