Phosgene, a chemical warfare agent used in world war i, consists of 12.41% c, 16.17% o, and 71.69% cl. 1.00 l of this gas at stp has a mass of 4.42 g. what is the molecular formula of phosgene?

Answer is: formula of phosgene is COCl₂.
V = 1.00 L.
Vm = 22.4 L/mol.
n(phosgene) = V ÷ Vm.
n(phosgene) = 1.00 L ÷ 22.4 L/mol = 0.0446 mol.
m(phosgene) = 4.42 g.
M(phosgene) = m(phosgene) ÷ n(phosgene).
M(phosgene) = 4.42 g ÷ 0.0446 mol = 99 g/mol.
n(C) : n(O) : n(Cl) = ω(C)/Ar(C) : ω(O)/Ar(O) : ω(Cl)/Ar(Cl).
n(C) : n(O) : n(Cl) = 12.41/12 : 16.17/16 : 71.69/35.45.
n(C) : n(O) : n(Cl) = = 1 : 1 : 2.