Question

A hydrocarbon contains $20\%$ hydrogen and $80\%$ carbon. The empirical formula is:

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

Answer 1

Answer: (B)

Element	Percentage	Atomic mass	Relative number of atoms	Simplest ratio
$H$	$20$	$1$	$20$	$20/6.66=3$
$C$	$80$	$12$	$6.66$	$6.66/6.66=1$

$\therefore$ Empirical formula $=C{H}_3$