Write true or false. Cis-trans isomers have different dipole moments

Answer

To determine whether the statement "Cis-trans isomers have different dipole moments" is true or false, we can analyze the characteristics of cis and trans isomers.

### Step-by-Step Solution:

1. **Understanding Cis-Trans Isomers**:
- Cis-trans isomerism occurs in alkenes where there is restricted rotation around a double bond.
- In cis isomers, similar groups are on the same side of the double bond, while in trans isomers, similar groups are on opposite sides.

2. **Dipole Moment Definition**:
- The dipole moment is a measure of the separation of positive and negative charges in a molecule. It is a vector quantity, meaning it has both magnitude and direction.
- The dipole moment depends on the electronegativity of the atoms involved and the geometry of the molecule.

3. **Analyzing the Dipole Moment in Cis Isomers**:
- In a cis isomer, the similar groups (e.g., CH3) are on the same side, leading to a net dipole moment because the dipole vectors do not cancel out.
- For example, if we consider a molecule like 2-butene in its cis form (CH3-CH=CH-CH3), the dipole moments from the CH3 groups will add together, resulting in a non-zero dipole moment.

4. **Analyzing the Dipole Moment in Trans Isomers**:
- In a trans isomer, the similar groups are on opposite sides of the double bond. This arrangement causes the dipole moments to cancel each other out.
- For the trans form of 2-butene (CH3-CH=CH-CH3), the dipole moments from the CH3 groups will point in opposite directions, resulting in a net dipole moment of zero.

5. **Conclusion**:
- Since the cis isomer has a net dipole moment while the trans isomer has a dipole moment of zero, we can conclude that cis and trans isomers have different dipole moments.

### Final Answer:
**True**: Cis-trans isomers have different dipole moments.