The molecular mass of an organic compound is 90 and its %age composition is C- 26.6%; O=71.1%

and H=2.2%. Determine the molecular formula of the compound.

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Solution

Let the molar mass of compound is 100 g
Number of moles of C in compound = 26.6/12 = 2.216
Number of moles of O in Compound = 71.1/16 = 4.44
Number of moles of H in compound = 2.2/1 = 2.2
Simple whole number ratio of mole of C, O and H is 1 : 2 :1
Empirical Formula = CHO₂
Empirical formula mass = 12 g + 1 g + 32 g = 45 g
Molecular mass of the compound is 90 g
Molecular formula = (empirical formula)n
n = Molar mass/empirical formula mass
n = 90 /45 = 2
So the molecular formula would be (CHO₂)₂ = C₂H₂O₄

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The molecular mass of an organic compound is 90 and its %age composition is C- 26.6%; O=71.1% and H=2.2%. Determine the molecular formula of the compound.

The molecular mass of an organic compound is 90 and its %age composition is C- 26.6%; O=71.1%

and H=2.2%. Determine the molecular formula of the compound.