Which of the following is the correct structure for 2,3-dichlorobutane?

To arrive at the correct structure for 2,3-dichlorobutane, it's important to first understand the naming convention and structural representation of organic molecules.

The compound name "2,3-dichlorobutane" indicates a butane molecule (which has four carbon atoms in a straight chain) with chlorine (Cl) substituents on the second and third carbon atoms. The "2,3-" prefix specifies that the chlorine atoms are located on the second and third carbons of a linear butane chain.

In the correct structure, which is represented as CH3-CH-Cl-CH-Cl-CH3, you can clearly see that there are four carbon atoms (counting from left to right: C1, C2, C3, and C4). The chlorines are appropriately placed on the second and third carbon atoms. The remaining hydrogen atoms fill in the unsatisfied valencies according to carbon's tetravalency.

The other structures do not meet the criteria specified by the IUPAC name:

• The first choice, CH3-CH-CH2-CH3, does not have any chlorine atoms at all and represents straight-chain butane (which is not what we need).

• The second choice,