Assertion : Boiling points of cis-isomers are higher than trans - isomers.
Reason : Dipole moments of cis - isomers are higher than trans - isomers.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion
B. If both assertion and reason are true and the reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If the assertion and reason both are false.

Explanation

To solve the question regarding the assertion and reason about the boiling points of cis and trans isomers, we can break it down into a step-by-step analysis.

### Step 1: Understanding the Assertion
The assertion states that the boiling points of cis-isomers are higher than those of trans-isomers. This is a claim that needs to be evaluated based on the properties of these isomers.

**Hint:** Consider the molecular structure and intermolecular forces of cis and trans isomers.

### Step 2: Analyzing the Reason
The reason provided is that the dipole moments of cis-isomers are higher than those of trans-isomers. This is crucial because dipole moments influence the strength of intermolecular forces, particularly dipole-dipole interactions.

**Hint:** Recall how molecular polarity affects boiling points due to intermolecular forces.

### Step 3: Comparing Dipole Moments
Cis-isomers typically have higher dipole moments than trans-isomers because the polar bonds in cis configurations do not cancel out due to their geometric arrangement. In contrast, trans-isomers often have their dipole moments cancel out, resulting in a lower overall dipole moment.

**Hint:** Visualize the molecular geometry of cis and trans isomers to understand the cancellation of dipole moments.

### Step 4: Relating Dipole Moments to Boiling Points
Higher dipole moments in cis-isomers lead to stronger dipole-dipole interactions among the molecules. Stronger intermolecular forces require more energy to overcome, which translates to higher boiling points.

**Hint:** Think about how stronger intermolecular forces correlate with the energy required to change from liquid to gas.

### Step 5: Conclusion
Since both the assertion and the reason are true, and the reason correctly explains the assertion, we conclude that the statement is valid.

**Final Answer:** Both the assertion and reason are true, and the reason is the correct explanation for the assertion.

### Summary of Steps:
1. Understand the assertion about boiling points.
2. Analyze the reason regarding dipole moments.
3. Compare the dipole moments of cis and trans isomers.
4. Relate dipole moments to boiling points through intermolecular forces.
5. Conclude the validity of both statements.