which term describes this reaction? addition condensation elimination substitution

Answer:

A. addition

Explanation:

Step1: Analyze reaction type

In the reaction, a double - bond in ethene ($C_2H_4$) is broken and two chlorine atoms are added across the double - bond to form 1,2 - dichloroethane ($C_2H_4Cl_2$). This is characteristic of an addition reaction. In an addition reaction, atoms or groups are added to a molecule containing a multiple bond (double or triple bond). In condensation reactions, a small molecule is eliminated during the reaction. In elimination reactions, atoms or groups are removed from a molecule to form a multiple bond. In substitution reactions, one atom or group is replaced by another atom or group. So this is an addition reaction.