Question

What are alkanes, alkenes, and alkynes?

Answer 1

Before understanding each of these 3 types, you need to know that alkanes, alkenes & alkynes are hydrocarbons .

Explanation:

Hydrocarbons are organic compounds which only consist of carbon (`C`) and hydrogen (`H`) as their elements.

Alkanes are a group of acyclic, saturated hydrocarbons. These are contain carbon - carbon (`C-C`) single bonds. The single bond is made up of one `sigma` (sigma) bond.
Their general formula is `C_nH_(2n+2)` . [Here, `n` stands for the number of carbon atoms].
Each atom has an `sp^3` hybridization in an alkane. The hydrogen atoms are always linked to a carbon atom.

`->` Examples : Methane (`CH_4`, where `n=1`); Butane* (`C_4H_10`)

Alkenes and alkynes are unsaturated hydrocarbons.

Unsaturated hydrocarbons are those in which you have atleast one carbon - carbon double bond (`C = C`), or atleast one carbon - carbon triple bond.

In the case of alkenes , they have atleast one carbon- carbon double bond. Their general formula is `C_nH_(2n)`. From the formula, you can notice that alkenes only have 2 `H` atoms lesser than the corresponding alkane.
The carbon - carbon double (`C = C`) bond consists of one `sigma` and one `pi` (pi) bond.

`->` Examples : Ethylene (`C_2H_2`) or ethene; Pentene (`C_5H_10`).

Alkynes are unsaturated hydrocarbons which have atleast one carbon- carbon triple bond. Their general formula is `C_nH_(2n-2)`. You can see that these have 2 hydrogen atoms less than their corresponding alkane.

`->` Examples : Acetylene (called ethyne) i.e. `C_2H_2`;
Propyne (`C_3H_4`).

I hope this helps!