Question

An organic compound contains $C=74.0\%$, $H=8.65\%$ and $N=17.3\%$. Its empirical formula is:

• A. $C_5{H}_{8}N$
• B. $C_{10}{H}_{12}N$
• C. $C_5{H}_{7}N$
• D. $C_{10}{H}_{14}N$

Answer 1

The correct option is C $C_5{H}_{7}N$

Let us consider the problem:
Element No. of Moles Simple Ratio
$C=74$ $74/12=6.1$ $6.1/1.2=5.08$ or $5$ &
$H=8.65$ $8.65/1=8.65$ $8.6/1.2=7.16$ or 7$

$N=17.3$ $17.3/14=1.2$ $1.2/1.2=1$ or $1$

Therefore the empirical formula is $C_5{H}_{7}N.$