Isomers exhibited by what diols
Answers
Isomerism is the phenomenon of exhibiting two or more compounds with same molecular formula but different physical and chemical properties.
Isomers are the compounds showing different physical and chemical properties but same molecular formula.
The isomerism in organic compounds can be classified broadly into:
Structural isomerism (constitutional isomerism) Stereo isomerism
The structural isomerism or constitutional isomerism arises when atoms within a molecule are arranged in different orders. The structural isomers have the same molecular formula but different structural formulae.
The structural isomers usually show different physical and chemical properties.
The structural isomerism is further divided into:
* Chain isomerism
* Positional isomerism
* Functional isomerism
* Metamerism
* Tautomerism
The chain isomerism arises due to different arrangements of carbon atoms leading to linear and branched chains. The chain isomers have same molecular formula but different types of chains i.e., linear and branched.
The chain isomers have almost similar chemical properties but different physical properties. For example, the branched chain isomers have lower boiling points than that of their linear counterparts. It is because, the linear ones have more surface area of contact and hence the intermolecular forces of attraction are maximum.
E.g. Two chain isomers possible with the molecular formula, C4H12.
n-butane: a linear chain isomer.
isobutane (or 2-methylpropane): a branched isomer
chain isomers: butane and isobutane
POSITIONAL ISOMERISM
The positional isomerism arises due to different positions of side chains, substituents, functional groups, double bonds, triple bonds etc., on the parent chain.
E.g.
1) Propyl chloride and isopropyl chloride are the positional isomers with the molecular formula, C3H7Cl. These isomers arise due to difference in the position of the chloro group on the main chain.
position isomers: 1-chloropropane and 2-chloropropane
2) In the following positional isomers i.e., but-1-ene and but-2-ene the position of double is different but they have same molecular formula, C4H8.
position isomerism: 1-butene and 2-butene
3) The functional group, -OH is at different positions on the main chain of the following alcohols. They have the same molecular formula, C3H7OH. position isomers: propan-1-ol and propan-2-ol
4) In the following positional isomers i.e., ortho xylene, meta xylene and para xylene, the relative positions of methyl groups on the benzene ring are different positional isomers of xylenes
FUNCTIONAL ISOMERISM :
The functional isomerism arises due to presence of different functional groups. The functional isomers have the same molecular formula but possess different functional groups.
The functional isomers show different physical as well as chemical properties.
E.g.
1) The dimethyl ether is the functional isomer of ethyl alcohol. Both have the same molecular formula, C2H6O. However they have different functional groups.
functional isomers: ethyl alcohol and dimethyl ether
2) Acetaldehyde is a functional isomer of acetone. They have the same molecular formula, C3H6O but different functional groups. Acetaldehyde contains aldehyde, -CHO functional group, whereas acetone has ketone, >C=O functional group.
functional isomerism: acetaldehyde and acetone
3) Both Acetic acid and methyl formate are also functional isomers. They have the same molecular formula, C2H4O2. Acetic acid is a carboxylic acid with -COOH group whereas methyl formate is an ester with -COOCH3 group.
functional isomerism: acetic acid and methyl formate