Question

There is only one compound that is named 1,2-diiodoethane, but there are two distinct compounds that can be named 1,2-diiodoethene. Why? Because 1,2-diiodoethane has more hydrogen atoms. There is a rotation about the C-C bond in 1,2-diiodoethane, and there isn’t about the C-C bond in 1,2-diiodoethene. There is a rotation about the C-C bond in 1,2-diiodoethene, and there isn’t about the C-C bond in 1,2-diiodoethane. Because the compounds have different molar masses

Answer 1

There is a rotation about the C-C bond in 1,2-diiodoethane, and there isn’t about the C-C bond in 1,2-diiodoethene

Step-by-step explanation:

This is because of geometric isomerism in 1,2-diiodoethene, the double bond hinders the free rotation around the c-c double bond, but it is free to rotate in 1,2-diioethane because there is no double bond therein