Question

See Figures 4.5a and 4.7. Can propane (C3H8) form isomers? Explain.

Short answer

No, propane cannot form isomers as it contains only three carbon atoms which cannot form a branched-chain structure.

Step-by-step solution

Introduction to hydrocarbons and isomers

Organic compounds contain carbon, hydrogen, and oxygen that are the main constituents in living organisms' structure. Hydrocarbons are carbon skeletons to which hydrogen atoms are attached at their free ends.

Based on the number of carbon atoms, alkanes are named methane, ethane, propane, butane, etc. If a double bond links two carbon atoms, they are called alkenes.

Isomers are compounds with the same number of carbons but different arrangements of the carbon skeleton.Their structure and properties differ as the number of carbon atoms differs, which affects the ability to form isomers.

Isomerism is of two primary types—structural isomerism and stereoisomerism. The structural isomerism includes isomers based on-chain, position, functional group, tautomerism, and metamerism. Stereoisomers are either optical or geometrical isomers.

If the number of carbon atoms in a hydrocarbon chain increases, the tendency to form isomers also increases.

Structural formula of propane

The structure of propane is composed of three carbons and eight hydrogen atoms. Its molecular formula is C₃H₈. The structural formula is as follows:

Isomers of propane

The atoms of propane are not diverse. Propane cannot form structural isomers because the three carbons atoms can attach only in a straight line. As there is no double bond in propane, the cis-trans isomers are not possible. Each carbon atom has at least two hydrogen atoms attached to it to make the molecule symmetrical.