Question

An organic compound contains carbon and hydrogen. Its elemental analysis gave $C-75\%$ and $H-25\%$. The empirical formula of the compound would be:

• A. $C{H}_4$
• B. $C{H}_3$
• C. $C{H}_2$
• D. $CH$

Answer 1

The correct option is A $C{H}_4$

For calculating the empirical formula,

$\begin{array}{ccccc}\text{Element}& \text{\% in compound}& \text{Atomic mass}& \text{No. of moles}& \text{Simple ratio}\\ C& 75& 12& \frac{75}{12}=6.25& \frac{6.25}{6.25}=1\\ H& 25& 1& \frac{25}{1}=25& \frac{25}{6.25}=4\end{array}$

So, the empirical formula is $C{H}_4$