Question

Select the formulae of alkanes, alkenes, and alkynes from the following list:

${\mathrm{CH}}_4,{\mathrm{C}}_2{\mathrm{H}}_4,{\mathrm{C}}_2{\mathrm{H}}_6,{\mathrm{C}}_2{\mathrm{H}}_2,{\mathrm{C}}_3{\mathrm{H}}_6,{\mathrm{C}}_3{\mathrm{H}}_8,{\mathrm{C}}_3{\mathrm{H}}_4,{\mathrm{C}}_4{\mathrm{H}}_{10},{\mathrm{C}}_4{\mathrm{H}}_8,{\mathrm{C}}_4{\mathrm{H}}_6$

Answer 1

Step 1:

The organic compounds consisting of Carbon $\left(\mathrm{C}\right)$ and Hydrogen $\left(\mathrm{H}\right)$ atoms are known as hydrocarbons. Hydrocarbons are of two types depending upon the kind of bonds formed between Carbon-Carbon atoms:

1. Saturated hydrocarbons
2. Unsaturated hydrocarbons

Step 2:

Saturated hydrocarbons:

The organic compounds containing Carbon atoms have a single bond between two Carbon-Carbon $\left(\mathrm{C}-\mathrm{C}\right)$ atoms are called saturated hydrocarbons.

Alkanes contain only single bonds between Carbon and Hydrogen atoms are called saturated hydrocarbons.

The general formula of saturated hydrocarbons is $\left({\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}+2}\right)$.

So, the alkanes from the given list are $({\mathrm{CH}}_4,{\mathrm{C}}_2{\mathrm{H}}_6,{\mathrm{C}}_3{\mathrm{H}}_8,{\mathrm{C}}_4{\mathrm{H}}_{10})$.

Step 3:

Unsaturated hydrocarbons:

The organic compounds containing Carbon atoms having multiple bonds either double bonds or triple bonds between two Carbon-Carbon atoms are called unsaturated hydrocarbons.

Alkenes and alkynes are unsaturated hydrocarbons that contain double bonds and triple bonds between the Carbon-Carbon atoms.

The general formula of alkene is $\left({\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}}\right)$ and for alkyne is $\left({\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}-2}\right)$.

So, the alkenes from the given list are $({\mathrm{C}}_2{\mathrm{H}}_4,{\mathrm{C}}_4{\mathrm{H}}_8,{\mathrm{C}}_3{\mathrm{H}}_6)$

The alkynes from the given list are $({\mathrm{C}}_2{\mathrm{H}}_2,{\mathrm{C}}_3{\mathrm{H}}_4,{\mathrm{C}}_4{\mathrm{H}}_6)$.