Q. A hydrocarbon contains $20\%$ hydrogen and $80\%$ carbon. The empirical formula is:
ManipalManipal 2001Hydrocarbons
Solution:
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 $= CH _{3}$
| Element | Percentage | Atomic mass | Relative number of atoms | Simplest ratio |
|---|---|---|---|---|
| $H$ | $20$ | $1$ | $20$ | $20/6.66=3$ |
| $C$ | $80$ | $12$ | $6.66$ | $6.66/6.66=1$ |