A COMPOUND ON ANALYSIS GAVE THE FOOLOWING % COMPOSITION

Na=14.31%  S= 9.97%  H=6.22% O=69.50%  calculate the molecular formula of the compound on the assumption that all the hydroden in the compound is present in composition with oxygen as water of crystrallization. molecular mass of compound is 322.

Calculate empirical formula:

 

Element	Symbol	Percentage of element	At. Mass of element	Relative no. of atoms = Percentage/At. Mass	Simplest atomic ratio	Simplest whole no. atomic ratio
Sodium	Na	14.31	23	14.31/23=0.62	0.62/0.31=2	2
Sulphur	S	9.97	32	0.31	1	1
Hydrogen	H	6.22	1	6.22	20	20
Oxygen	O	69.50	16	4.34	14	14

 

Thus, the empirical formula of the compound is = Na₂SH₂₀O₁₄

The empirical formula mass of the compound = 2×23+1×32+20×1+14×16= 322

Now, calculate value of n = Molecular mass / Empirical mass = 322/322=1

Finally, calculate molecular formula of the compound = n × Empirical formula= 1 × Na₂SH₂₀O₁₄

Hence, molecular formula of the compound = Na₂SH₂₀O₁₄