Question 11 - Past Year - 3 Mark Questions - Chapter 4 Class 10 - Carbon and its Compounds

An aldehyde as well as a ketone can be represented by the same molecular formula, say C ₃ H ₆ O. Write their structures and name them. State the scientific relation between the two.

Answer

• Aldehydes are carbon compounds in which a carbon atom, in the carbon chain, shares a double bond with an oxygen atom and a single bond with a hydrogen atom.
• Ketones are carbon compounds in which a carbon atom, in the carbon chain, shares a double bond with an oxygen atom.

Any carbon compound with 3 carbon atoms in the carbon chain starts with “prop” and having an aldehyde functional group ends with “al”.

So,the aldehyde with molecular formula C ₃ H ₆ O is propanal.

Any carbon compound with 3 carbon atoms in the carbon chain starts with “prop” and having a ketone functional group ends with “one”.

So,the ketone with molecular formula C ₃ H ₆ O is propanone.

Isomers are compounds having the same molecular formula but different functional groups/structural formula.

Propanal and propanone have the same molecular formula i.e. C ₃ H ₆ O but different functional groups ( ketone and aldehyde respectively). Therefore, they are isomers.