Question 1

One of the products formed in the following reaction is

Accepted Answer

Cyclohexylmagnesium bromide is a Grignard reagent, which acts as a strong base. Cyclohexylamine contains active (acidic) hydrogen atoms attached to the nitrogen atom. When a Grignard reagent reacts with a compound containing an active hydrogen, an acid-base reaction occurs preferentially. The Grignard reagent abstracts a proton to form the corresponding alkane. C_6H_ 11 MgBr + C_6H_ 11 NH_2 C_6H_ 12 + C_6H_ 11 NHMgBr Thus, cyclohexane (C_6H_ 12 ) is formed as one of the products.

Question 2

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : undergoes S _ N 2 reaction faster than Reason (R) : Iodine is a better leavin

Accepted Answer

Rate of S _ N 2 Leaving tendency of leaving group. Iodine is better L.G. than chlorine due to its bigger size.

Question 3

How many products (including stereoisomers) are expected from monochlorination of the following compound?

Accepted Answer

Total =6 (including stereo isomers)

Question 4

The following reaction method is not suitable for the preparation of the corresponding haloarene products, due to high reactivity of halogen, when X is :

Accepted Answer

- Aryl chlorides and bromides can easily be prepared by electrophilic substitution of arenes (toluene) with Cl _2 and Br _2 respectively in the presence of Lewis acid catalyst ( Fe in dark). - Reaction with I _2 is reversible and requires the presence of oxidising agent. - Corresponding fluoroarene is not prepared by this method due to high reactivity of fluorine. Hence, ' X ' is F.

Haloalkanes and Haloarenes — Previous Year Questions & Solutions