Question

Which of the following is the geminal dichloride?

• A. 1,1-Dichloropropane
• B. 1,2-Dichloropropane
• C. 1,3-Dichloropropane
• D. 2,3-Dichloropropane

Hint:

Remember that "geminal" (gem-) refers to two substituents being on the same carbon atom, while "vicinal" (vic-) refers to two substituents being on adjacent carbon atoms. In the context of dihalides, a geminal dichloride has two chlorine atoms on the same carbon, and a vicinal dichloride has two chlorine atoms on adjacent carbons.

Answer 1

The Correct Option is A

Geminal dihalides (or gem-dihalides) are organic compounds in which two halogen atoms are bonded to the same carbon atom.
Let's examine the structures corresponding to each name:
Option (A) 1,1-Dichloropropane: The structure is \( CH_3CH_2CHCl_2 \).
The two chlorine atoms are attached to the first carbon atom.
This is a geminal dichloride.

Option (B) 1,2-Dichloropropane: The structure is \( CH_3CHClCH_2Cl \).
The two chlorine atoms are attached to adjacent carbon atoms (carbon 1 and carbon 2).
This is a vicinal dichloride.

Option (C) 1,3-Dichloropropane: The structure is \( ClCH_2CH_2CH_2Cl \).
The two chlorine atoms are attached to carbon 1 and carbon 3, which are separated by one carbon atom.
This is neither a geminal nor a vicinal dichloride.

Option (D) 2,3-Dichloropropane: The structure is \( CH_3CHClCHCl \).
The two chlorine atoms are attached to adjacent carbon atoms (carbon 2 and carbon 3).
This is a vicinal dichloride.
Therefore, 1,1-dichloropropane is the geminal dichloride among the given options.