Which of the following is known as gem - dibromide ?

Options

A. `CH_3CH(Br)CH(Br)CH_3`
B. `CH_2(Br)CH_2CH_2`
C. `CH_2BrCH_2Br`
D. `CH_3CBr_2CH_3`

Answer

To determine which compound is known as gem-dibromide, we need to understand the structure of gem-dibromide. The term "gem" refers to a specific arrangement of substituents on a carbon atom in organic chemistry.

### Step-by-Step Solution:

1. **Understanding Gem-Dibromide**:
- The term "gem-dibromide" indicates that there are two bromine (Br) atoms attached to the same carbon atom. The prefix "gem" stands for "geminal," which means that the two substituents (in this case, bromine atoms) are on the same carbon.

2. **Identifying the Structure**:
- A gem-dibromide would have the following structure:
- R - C(Br)(Br) - R'
- Here, R and R' can be hydrogen atoms or alkyl groups, but the key point is that both bromine atoms are attached to the same carbon atom.

3. **Analyzing the Options**:
- If given multiple structures, we need to identify which one has both bromine atoms attached to the same carbon. For example:
- CH3 - C(Br)(Br) - CH3 (This is a gem-dibromide)
- CH2Br - CH2Br (This is not a gem-dibromide as the bromines are on different carbons)
- CH3 - CH(Br) - CH2Br (This is also not a gem-dibromide)

4. **Conclusion**:
- The correct answer is the structure where both bromine atoms are attached to the same carbon atom, which is the definition of gem-dibromide.