Question

The percentage of $C$, $H$ and $N$ in an organic compound are $40$%, $13.3$% and $46.7$% respectively. The empirical formula is:

• A. $C_3{H}_{13}{N}_3$
• B. $C{H}_{2}N$
• C. $C{H}_{4}N$
• D. $C{H}_{6}N$

Answer 1

The correct option is C $C{H}_{4}N$

We have the percentage by weight of various atoms in the organic compound. Using this, we can calculate the percentage of the number of atoms by simply dividing the mass percent by atomic mass.

Ratio of atoms $=$ $C$ : $H$ : $N=\frac{40}{12}:\frac{13.3}{1}:\frac{46.7}{14}$

$=3.33:13.33:3.33=1:4:1⟹Empiricalformula=C{H}_{4}N$.