What is the effect of a strong electron-withdrawing group on the reactivity of a benzene ring in electrophilic substitution?
Practice Questions
1 question
Q1
What is the effect of a strong electron-withdrawing group on the reactivity of a benzene ring in electrophilic substitution?
Increases reactivity
Decreases reactivity
No effect
Reverses reactivity
A strong electron-withdrawing group decreases the reactivity of the benzene ring in electrophilic substitution by destabilizing the sigma complex.
Questions & Step-by-step Solutions
1 item
Q
Q: What is the effect of a strong electron-withdrawing group on the reactivity of a benzene ring in electrophilic substitution?
Solution: A strong electron-withdrawing group decreases the reactivity of the benzene ring in electrophilic substitution by destabilizing the sigma complex.
Steps: 7
Step 1: Understand what a benzene ring is. It is a stable structure made of six carbon atoms arranged in a circle, with alternating double bonds.
Step 2: Learn about electrophilic substitution. This is a reaction where an electrophile (a positively charged species) replaces a hydrogen atom on the benzene ring.
Step 3: Know what an electron-withdrawing group is. It is a group that pulls electrons away from the benzene ring, making it less electron-rich.
Step 4: Recognize that a strong electron-withdrawing group significantly decreases the electron density of the benzene ring.
Step 5: Understand the sigma complex. This is a temporary structure formed during the electrophilic substitution process when the electrophile attaches to the benzene ring.
Step 6: Realize that if the benzene ring has a strong electron-withdrawing group, the sigma complex becomes less stable because it has less electron density to stabilize the positive charge.
Step 7: Conclude that because the sigma complex is less stable, the overall reactivity of the benzene ring in electrophilic substitution decreases.
