Q22E - Organic Chemistry (Mcmurry)

Question

Question: Cis-1, 2-Dichloroethylene, and trans-1, 2-dichloroethylene are isomers, compounds with the same formula but different chemical structures. Look at the following electrostatic potential maps, and tell whether either compound has a dipole moment.

Step-by-Step Solution

Answer

Cis-1, 2-Dichloroethylene has a higher dipole as compared to trans-1, 2-dichloroethylene which shows nearly zero dipole moment.

Step 1: Electrostatic potential maps and Dipole moment

Electrostatic potential maps are the three-dimensional charge distribution of molecules.

Electrostatic potential maps are also called electrostatic potential surfaces.

Measurement of separation of two opposite electric charges is called a dipole moment.

Step 2: Dipole moment of cis 1, 2 dichloroethylene

In 1, 2 dichloroethylene dipole moment of polar C-Cl bond is in the same direction so the resultant dipole moment is the sum of the dipole moments of two C-Cl bonds. Dipole moment direction in 1, 2 dichloroethylene is as shown below;

Step 3: Dipole moment of Trans 1, 2 dichloroethylene

In trans 1, 2 dichloroethylene dipole moment of polar C-Cl bonds are in the opposite direction so both the dipole moment cancels each other and the resultant dipole moment for the trans 1, 2 dichloroethylene molecule is zero.