The correct option is
D ![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1217797/original_8d.png)
Products formed is a pair of enantiomer
(a) The bond strength order is:
C−H<C−D<C−T
During sulphonation electrophile react the benzene ring to form a sigma complex. To regain aromaticity, hydrogen atom is eliminated. Since
C−H bond is weaker than
C−D bond. Hence rate of sulphonation for
C6H6 is relatively faster than
C6D6.
(b) Salicylic acid gives 2,4,6-tribromophenol on treatment with
Br2/H2O.
(c) When
HCOOEt is treated with excess of
MeMgBr followed by hydrolysis, it will result in the formation of secondary alcohol.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1215043/original_8an2.png)
(d)
SN2 reaction proceeds through inversion of configuration. Since only isomers is taken so it will give a single product.