For the compound $C_2{H}_4{\mathrm{Cl}}_2$ (1,2-dichloroethane), how many chemically non-equivalent carbon atoms are present?

• A. $4$
• B. $1$
• C. $2$
• D. $3$

Answer: (B)

Verified step by step guidance

1. Identify the molecular structure of 1,2-dichloroethane, which has the formula C\_2H\_4Cl\_2, with chlorine atoms attached to each of the two carbon atoms in the ethane backbone.
2. Draw the structure to visualize the molecule: two carbon atoms connected by a single bond, each bonded to two hydrogens and one chlorine atom.
3. Determine the symmetry of the molecule by checking if the two carbon atoms are in identical chemical environments. Since each carbon is bonded to one chlorine and two hydrogens, their environments are the same.
4. Recall that chemically equivalent atoms have the same connectivity and environment, so if the two carbons have identical surroundings, they are chemically equivalent.
5. Conclude that there is only one type of chemically non-equivalent carbon atom in 1,2-dichloroethane.