Question

A carbohydrate contains $40\%$ carbon and $6.66$ hydrogen. Determine molecular formula if molecular weight is $180$.

Answer 1

Given:-

Carbon $⟶40$%

Hydrogen $⟶6.66$%

Oxygen $⟶100-(40+6.66)=53.34$%

Carbon Hydrogen Oxygen

$\frac{40}{12}$ $\frac{6.66}{1}$ $\frac{53.34}{16}$

$3.33$ $6.66$ $3.33$

Simplest ratio= $C{H}_{2}O$

Molecular formula mass= n $\times$ structural formula mass

$\Rightarrow 180=n\times 30$

$\Rightarrow n=6$

Molecular formula= $C_6{H}_{12}{O}_6$