Question

Considering all possible isomeric ketones, including stereoisomers of a compound having a molecular weight of $100$. All these isomers are independently reacted with NaBH${}_4$. The total number of ketones that give a racemic product(s) is/are:

[Note: stereoisomers are also reacted separately]

Answer 1

$C_n{H}_{2n}O\Rightarrow 12\times n+2n\times 1+16=100$

$\Rightarrow n=6$

1st ketone the R and S both reacts separately with $NaB{H}_4$ to form diastereomeric pair.

The possible no. of isomers of $C_6{H}_{12}O$ are shown above in the figure.

Hence the correct answer is 5.