What are alkanes, alkenes, and alkynes?

1 Answer
Jun 6, 2018

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!