Q. What product would you expect from reaction of HCl with 1- ethylcyclopentene?

The reaction of HCl with 1-ethylcyclopentene would result in a Markovnikov addition of the HCl across the double bond of the ethylcyclopentene.

Here are the steps:

1. Identify the double bond in the 1-ethylcyclopentene. This is where the addition will occur.

2. The HCl will break apart into H+ and Cl-. The H+ ion will be attracted to the area of high electron density, which is the double bond.

3. The double bond will break, and the H+ ion will attach to one of the carbons. This will follow Markovnikov's rule, which states that the hydrogen will add to the carbon with the most hydrogen atoms already attached. In this case, the hydrogen will add to the carbon on the end of the double bond, not the one attached to the ethyl group.

4. The Cl- ion will then attach to the other carbon, where the double bond used to be.

5. The final product will be 1-chloroethylcyclopentane.