Question

Question: a. How many vinylic hydrogens does cyclopentene have?

b. How many allylic hydrogens does it have?

Short answer

Answer-

1. 2vinylic hydrogens
2. 4 allylic hydrogens

Step-by-step solution

Definition of vinylic hydrogens

Vinylic carbons are the sp²carbons in an alkene and a vinylic hydrogen is a hydrogen bound to a vinylic carbon.

Definition of allylic hydrogens

An allylic carbon is a sp³carbon that is next to a vinylic carbon., whereas an allylic hydrogen is a hydrogen attached to an allylic carbon.

Calculating vinylic and allylic carbon in cyclopentene-

• There are two sp² hybridized vinylic carbon in cyclopentene and hence it has 2 vinylic hydrogens.
• Similarly, there are 2 allylic carbons in cyclopentene which has 4 allylic hydrogens.