Which of the following hydrocarbons has the lowest dipole moment

Options

A.
B. `CH_(3)-HC = HC - CH_(3)`
C. `CH_(3)-CH_(2)CH=CH_(2)`
D. `CH_(2)=CH-CH=CH_(2)`

Explanation

To determine which of the given hydrocarbons has the lowest dipole moment, we need to analyze the symmetry and structure of each option. Here’s a step-by-step solution:

### Step 1: Understand Dipole Moment
The dipole moment is a measure of the polarity of a molecule. It occurs due to the difference in electronegativity between atoms and the geometry of the molecule. Symmetrical molecules tend to have a dipole moment of zero because the individual bond dipoles cancel each other out.

### Step 2: Analyze Each Hydrocarbon Option
1. **Option A: 1,2,3,4-2-methyl carbene**
- This structure is unsymmetrical, which means that it will have a net dipole moment due to the unequal distribution of charge.

2. **Option B: Symmetrical Hydrocarbon**
- This option is described as symmetrical and planar. A symmetrical and planar molecule will have a dipole moment of zero because the bond dipoles cancel each other out.

3. **Option C: Another Hydrocarbon**
- Without specific details, we can assume that if this hydrocarbon is also symmetrical, it may have a low dipole moment, but we need to compare it with the other options.

4. **Option D: Linear Geometry Hydrocarbon**
- If this hydrocarbon has a linear geometry and is symmetrical, it will also have a dipole moment of zero.

### Step 3: Compare the Options
- **Option A** has a dipole moment due to its unsymmetrical structure.
- **Option B** has a dipole moment of zero due to its symmetrical and planar structure.
- **Option C** needs more information, but if it is not symmetrical, it may have a dipole moment.
- **Option D** also has a dipole moment of zero if it is symmetrical and linear.

### Conclusion
The hydrocarbons with the lowest dipole moment are those that are symmetrical and planar or linear. Based on the analysis, **Option B** is confirmed to have the lowest dipole moment.

### Final Answer
**Option B** has the lowest dipole moment.

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