Question

Which of the following is a vicinal dihalide?

• A. 1,1-Dibromopropane
• B. 1,2-Dibromopropane
• C. 1,3-Dibromopropane
• D. Benzal dibromide
• E. 1,3-Dibromobutane

Hint:

Geminal = Same carbon; Vicinal = Adjacent carbons.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
This question asks to identify a "vicinal dihalide". We need to know the definitions of different types of dihalides based on the relative positions of the halogen atoms.
Step 2: Detailed Explanation:
There are two main classifications for dihalides where the halogen atoms are on adjacent or the same carbon atoms: - Vicinal Dihalide: The two halogen atoms are attached to adjacent carbon atoms (i.e., on carbons 1 and 2, or 2 and 3, etc.). The term "vicinal" comes from the Latin vicinus, meaning neighbor. - Geminal Dihalide: The two halogen atoms are attached to the same carbon atom. The term "geminal" comes from the Latin geminus, meaning twin. Now let's analyze the options: - (A) 1,1-Dibromopropane: The two bromine atoms are on carbon-1. This is a geminal dihalide. - (B) 1,2-Dibromopropane: The two bromine atoms are on carbon-1 and carbon-2, which are adjacent carbons. This is a vicinal dihalide. - (C) 1,3-Dibromopropane: The two bromine atoms are on carbon-1 and carbon-3. These carbons are not adjacent. - (D) Benzal dibromide (Benzylidene dibromide): The structure is C\(_6\)H\(_5\)-CHBr\(_2\). The two bromine atoms are on the same carbon atom. This is a geminal dihalide. - (E) 1,3-Dibromobutane: The two bromine atoms are on carbon-1 and carbon-3. These carbons are not adjacent. Step 3: Final Answer:
The vicinal dihalide among the options is 1,2-Dibromopropane.