If ketone and an alkene are in the same compound and the compound is made to react with H 2 - Ni 1 equivalent then alkene will attack or carbonyl-

You visited us 7 times! Enjoying our articles? Unlock Full Access!

Introduction

If ketone and...

Question

If ketone and an alkene are in the same compound and the compound is made to react with H²/ Ni (1 equivalent ) then alkene will attack or carbonyl ?

Open in App

Solution

You are asking the preference of hydrogen on carbonyl group and alkene group
Consider the following compound
CH2=CH-CH2-CHO
If it is reacted with one mole H2 then the preference will be on alkene over carbonyl group.
This is because

All the reaction that is taking place on alkene is electrophilic addition reactions. That means a positive charged H+ has to attach the molecule to give the product. Generation of H+ is easier so the reaction will take place in alkene

But all the reaction taking place in carbonyl group (C=O) is nucleophilic addition reactions. So the reaction has to start through negative ions. Generating H- ion is. not possible. So this hydrogenation is difficult to carry comparing with alkene.

Suggest Corrections

Similar questions

A compound 'X' reacts with conc. Sulphuric acid to give an alkene. The alkene reacts with bromine and subsequent treatment of the product with alcoholic KOH yields propyne. The formula of the compound is

Q. A ketone reacted with

C_{2} H_{5} M g B r

reagent followed by hydrolysis gave a product which on dehydration gives an alkene. The alkene on ozonolysis gave diethyl ketone and acetaldehyde. The ketone is:

Q. Assertion :Alkenes undergo electrophilic addition whereas aldehydes and ketones undergo nucleophilic addition. Reason: In alkenes the double bond joins two carbon atoms and there is no resultant polarity. In carbonyl compounds, the carbonyl group is highly polar and the high partial positive charge on the C atom makes it subsceptible to nucleophilic attack.

Q. In the reaction with

H C l

, an alkene reacts in accordance with the Markovnikov's rule, to give a product 1-chloro-1-methylcyclohexane. The possible alkene is:

Q. In the formation of alkene when alcoholic

K O H

reacts with

C H_{3} C H_{2} C l

. What is the attacking species in the reaction?

Join BYJU'S Learning Program