0

Guest

Courses New

Give reason for the following: (i) Aldehydes are more reactive than ketones towards nucleophilic reactions. (ii) pKa value of acetic acid is higher than pKa value of chloroacetic acid.

Give reason for the following:
(i) Aldehydes are more reactive than ketones towards nucleophilic reactions.
(ii) pKa value of acetic acid is higher than pKa value of chloroacetic acid.

Grade:Upto college level

1 Answers

Sunil Kumar FP
askIITians Faculty 183 Points
9 years ago
(1)Aldehydes are usually more reactive toward nucleophilic substitutions than ketones because of both steric and electronic effects. In aldehydes, the relatively small hydrogen atom is attached to one side of the carbonyl group, while a larger R group is affixed to the other side. In ketones, however, R groups are attached to both sides of the carbonyl group. Thus, steric hindrance is less in aldehydes than in ketones.
(2)pkaofacetic acid is 4.23 and chloroacetic acid is 2.3.​
pKavalue depends upon the strength of acid. The stronger acid will have lesser pKavalue and weaker acid will have higher pKa value.The value indicates that chloroacetic acid is stronger acid than acetic acid.
This can be explained on the basis of inductive effect of Cl.Cl being highly electronegative will pull the electrons towards itself This will polarize the C-Cl bond and in turn also polarize the C-O and O-H bonds.Due to this there would be easy removal of H+ ion. Moreover anion formed by removal of H+will also stabilized by electron pulling nature of Cl.

Think You Can Provide A Better Answer ?

Other Related Questions on Physical Chemistry

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More