What stabilizes a carbocation in a nucleophilic substitution reactions?

Essentially, it is the adjacent atoms or groups attached to the central carbon atom which have the ability to stabilise or destabilise a carbocation. The formation of this carbocation is what determines the rate of the reaction (as the Rate Determining Step), therefore the level of stability of the carbocation intermediate will determine how quickly or slowly this intermediate is formed; a stable intermediate will form quicker than a more unstable one. 

Large bulky alky groups possess electron donating (ED) effects, meaning it pushes electron density onto the central positively charged carbon atom through resonance. The fewer ED groups which are attached to the central carbon the less stability will be given to the carbocation via resonance. A general rule of thumb in order of stability: tertiary carbon > secondary > primary. Also important to note that groups such as nitro or carbonyl groups will have the opposite effect as they possess a electron withdrawing (EW) effect. 

AH
Answered by Alfie H. Chemistry tutor

3018 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

Calculate the pH of 0.1M Benzoic Acid (C6H5COOH). Ka = 6.3x10-5 M


What affects the boiling point of an alkane and why?


Explain: 1. Why butanoic acid has a higher boiling point than butan1-ol? 2. Why carboxylic acids of short chain length are more soluble in water than those with longer carbon chain length?


What evidence is there for delocalisation in benzene?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning