A hydrocarbon contains 20 % by mass of hydrogen. What is its empirical formula?

Answer: C4H

Explanation:

An hydrocarbon is a compound with carbon and hydrogen atoms only covalently linked together.

Thus, all hydrocarbons have a basic formula of CH.

Now, mass of hydrocarbon = 100%

Mass of hydrogen = 20%

Mass of carbon = (100% - 20%) = 80%

i. e Carbon : Hydrogen

= 80% : 20%

= (80% / 20%)

= 4 : 1

Thus, the empirical formula of the hydrocarbon is C4H