Which of the following connot be written in an isomeric form ?A CH3 – CH(OH) – CH2 – CH3 B CH3 – CHO C CH2 = CH – Cl D Cl – CH2CH2 – Cl

To determine which of the given compounds cannot be written in an isomeric form, we need to analyze each compound and its potential isomers.

A) CH3 – CH(OH) – CH2 – CH3: This compound is a straight-chain alcohol, also known as butanol. It can have isomers by changing the position of the hydroxyl group (OH) along the carbon chain. Therefore, it can be written in an isomeric form.

B) CH3 – CHO: This compound is an aldehyde, specifically known as acetaldehyde. It has a carbonyl group (C=O) attached to a methyl group. Acetaldehyde cannot have isomers since the carbonyl group is always located at the end of the carbon chain. Therefore, it cannot be written in an isomeric form.

C) CH2 = CH – Cl: This compound is an alkene, specifically known as vinyl chloride. It has a double bond between two carbon atoms and a chlorine atom attached to one of the carbons. Alkenes can have isomers by changing the position of the double bond along the carbon chain. Therefore, it can be written in an isomeric form.

D) Cl – CH2CH2 – Cl: This compound is a symmetrical alkane, specifically known as 1,2-dichloroethane. It has two chlorine atoms attached to the second carbon atom in a straight carbon chain. Since it is symmetrical, it cannot have isomers. Therefore, it cannot be written in an isomeric form.

In conclusion, the compound that cannot be written in an isomeric form is B) CH3 – CHO.