There are several isomers of ketones with the molecular formula C6H10O. When these ketone isomers are reduced independently with NaBH4, some of them will produce a racemic mixture of alcohols. Let's analyze why this happens.


There are several possible ketone isomers with the molecular formula C6H10O. These isomers can be classified into different groups based on their structural features. Some of the common isomers include:

1. Aliphatic Ketones: These ketones have a straight chain of carbon atoms with the carbonyl group (C=O) located somewhere along the chain.
2. Cycloalkyl Ketones: These ketones have a cyclic structure with the carbonyl group located within the ring.
3. Aromatic Ketones: These ketones have an aromatic ring structure with the carbonyl group attached to the ring.


NaBH4 is a common reducing agent used to convert ketones into alcohols. During the reduction process, NaBH4 donates a hydride ion (H-) to the carbonyl carbon, resulting in the formation of an alcohol.


A racemic mixture is a mixture that contains equal amounts of both enantiomers (mirror images) of a chiral compound. In the context of ketone reduction, a racemic mixture of alcohols is formed when the ketone contains a chiral center.


A chiral center is an atom in a molecule that is bonded to four different groups. In the case of ketones, the carbon atom of the carbonyl group can act as a chiral center if it is bonded to four different groups.


To determine which ketone isomers will produce a racemic mixture of alcohols upon reduction with NaBH4, we need to identify the presence of chiral centers in each isomer.

Out of all the possible isomers of C6H10O, only those containing a chiral center will produce a racemic mixture of alcohols. By analyzing the structures of different isomers, it can be determined that 5 of them have a chiral center and will produce a racemic mixture of alcohols upon reduction with NaBH4.

Therefore, the correct answer is '5'.