Pentane and 2-methylbutane differ in the arrangement of carbon atoms, thus showing chain isomerism.

2-pentene can exist in cis and trans forms due to the presence of a double bond.

Lactic acid has a chiral center and can exist as two enantiomers, thus exhibiting optical isomerism.

1-bromopropane and 2-bromopropane differ in the position of the bromine atom, showing structural isomerism.

Keto-enol tautomerism is a classic example of tautomeric isomerism.

Hydrogen isomerism is not a recognized type of isomerism in chemistry.

D-Glucose and L-Glucose are mirror images of each other, making them enantiomers.

1-pentanol and 2-pentanol differ in the position of the hydroxyl group, making them structural isomers.

D-Glucose and L-Glucose are mirror images of each other, making them enantiomers.

C2H6 (ethane) and C2H5OH (ethanol) have different functional groups, making them functional isomers.

Cis-2-butene and trans-2-butene differ in the arrangement of groups around the double bond, making them geometric isomers.

Ethyl alcohol (ethanol) and dimethyl ether have the same molecular formula but different structures.

Isomers can exist in the same physical state, such as liquid or solid.

Isomers have the same molecular formula but differ in the arrangement of atoms.

Isomers can have different physical and chemical properties despite having the same molecular formula.

Optical isomers, or enantiomers, rotate plane-polarized light in opposite directions.

Optical isomers, or enantiomers, rotate plane-polarized light in opposite directions.

1,2-dichloroethene can exist in cis and trans forms, demonstrating geometric isomerism.

1,3-butadiene can exhibit geometric isomerism due to the presence of double bonds.

Glucose and fructose are structural isomers as they have the same molecular formula but different structures.

Butane exhibits structural isomerism as it can exist as n-butane and isobutane.