MCQ
An organic compound has $\%$ of $C$ and $\%$ of $H$ in the ratio $6 : 1$ and $\%$ of $C$ and $\%$ of $O$ in the ratio $3 : 4$. The compound is
  • $HCHO$
  • B
    $C{H_3}OH$
  • C
    $C{H_3}C{H_2}OH$
  • D
    $(COOH)_2$

Answer

Correct option: A.
$HCHO$
a
An organic compound has $C$ and $H$ percentage in the ratio $6: 1$ by mass and $C$ and $O$ percentage in the ratio $3: 4$ by mass. Thus, the compound will contain $6 \,g$ of $C$ for each $g$ of $H$ and $8 \,g$ of $O$. The atomic masses of $C , H$ and $O$ are $12\,g / mol , 1\, g / mol , 16\, g / mol$ respectively.

The number of moles of $C =\frac{6 / g }{12 g / mol }=0.5\, mol$.

The number of moles of $H =\frac{1 / g }{1 g / mol }=1 \,mol$.

The number of moles of $O =\frac{8 / g }{16 g / mol }=0.5 \,mol$.

The mole ratio $C : H : O =0.5: 1: 0.5=1: 2: 1$

Hence, the compound is $CH _2 O$ or $HCHO$

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