Question

Write the type of attacking reagent and the type of reaction for the following:
(a)
Nitration of benzene to give nitrobenzene.
lar
HCN reacted with acetaldehyde to form acetaldehyde cyano hydrin.
(c)
Ethyl bromide with alcoholic KOH.​

Answer 1

Answer:

a)Nitration and sulfonation of benzene are two examples of electrophilic aromatic substitution. The nitronium ion (NO2+) and sulfur trioxide (SO3) are the electrophiles and individually react with benzene to give nitrobenzene and benzenesulfonic acid respectively.

Nitration of Benzene

The source of the nitronium ion is through the protonation of nitric acid by sulfuric acid, which causes the loss of a water molecule and formation of a nitronium ion

b)Cyanohydrins have the structural formula of R2C(OH)CN. The “R” on the formula represents an alkyl, aryl, or hydrogen. To form a cyanohydrin, a hydrogen cyanide adds reversibly to the carbonyl group of an organic compound thus forming a hydroxyalkanenitrile adducts (commonly known and called as cyanohydrins)

Answer 2

Nitration of benzene is Electrophilic Substitution

Explanation:

(a) Reagents used is - $HNO_3 + H_2SO_4$

Nitration of benzene is done by a mixture of $HNO_3 + H_2SO_4$ in concentrate form.

Type of reaction - Electrophilic substitution

(b) Reagents used is - Hydrogen cyanide

HCN reacted with acetaldehyde to form acetaldehyde cyano hydrin in which a hydrogen cyanide adds reversibly to the carbonyl group

Type of reaction - Acid Hydrolysis

(c) Reagents used is - KOH

When ethyl bromide reacts with alcoholic KOH, it undergoes beta elimination

Type of reaction - Elimination Reaction