Question

For which of the following compounds cis-trans isomers exists?

1. $C{H}_{3}CH=C{H}_2$

2. $C{H}_{3}CH=CHC{H}_{2}C{H}_3$

3. $C{H}_{3}CH=CHC{H}_3$

• A. both 2 and 3
• B. only 1
• C. only 2
• D. both 1 and 3

Answer 1

The correct option is A both 2 and 3

cis-trans isomers are also known as geometrical isomers or configurational isomers. Cis indicates that the functional groups are on the same side of the carbon chain, and trans indicates that the functional groups are on the opposite side of the carbon chain.

Here both the compounds cis, trans-pent-2-ene and cis, trans-but-2-ene.

cis-but-2-ene trans- but-2-ene