Question

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, $38.71\%$ and H, $9.67\%$. The empirical formula of the compound would be?

• A. $C{H}_{4}O$
• B. $C{H}_{3}O$
• C. $C{H}_{2}O$
• D. $CHO$

Answer 1

The correct option is B $C{H}_{3}O$

The empirical formula is to be calculated as:

Element	% Composition	Atomic Mass	Mole Ratio	Simple Ratio
C	38.71	12	$\frac{38.71}{12}=3.22$	$\frac{3.22}{3.22}=1$
H	9.67	1	$\frac{9.67}{1}=9.67$	$\frac{9.67}{3.22}=3$
O	100-(38.71+9.67) =51.62	16	$\frac{51.62}{16}=3.22$	$\frac{3.22}{3.22}=1$

Hence the empirical formula of the compound is $C{H}_{3}O$