JEE Main 12 Jan 2019 Morning Question 5

Question: $ CH _3CH _2-\underset{\begin{smallmatrix} | \\ Ph \end{smallmatrix}}{\overset{\begin{smallmatrix} OH \\ | \end{smallmatrix}}{\mathop{C}}},-CH _3 $ cannot be prepared by [JEE Main Online Paper Held On 12-Jan-2019 Morning]

Options:

A) $ PhCOCH _3+CH _3CH _2MgX $

B) $ HCHO+PhCH(CH _3)CH _2MgX $

C) $ PhCOCH _2CH _3+CH _3MgX $

D) $ CH _3CH _2COCH _3+PhMgX $

Show Answer

Answer:

Correct Answer: B

Solution:

Formaldehyde on reaction with Grignard’s reagent always forms primary alcohol.

The required product is tertiary alcohol.

Thus formaldehyde cannot be used to prepare it.