Assertion: Methyl cyanide has higher boiling point than methyl isocyanide.
Reason: Dipole moment of methyl cyanide is higher than that of methyl isocyanide.

Options

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

Answer

To solve the question regarding the assertion and reason provided, we will analyze both the assertion and the reason step by step.

### Step 1: Understanding the Compounds
- **Methyl Cyanide (Acetonitrile)**: The chemical formula is CH₃CN. It has a linear structure with a carbon triple-bonded to nitrogen.
- **Methyl Isocyanide**: The chemical formula is CH₃NC. It has a different structure where the nitrogen is bonded to the carbon with a single bond and has a lone pair of electrons.

### Step 2: Analyzing the Boiling Points
- **Boiling Point of Methyl Cyanide**: Methyl cyanide has a higher boiling point due to the presence of a strong dipole moment resulting from the polar C≡N bond. The linear structure allows for effective intermolecular dipole-dipole interactions.
- **Boiling Point of Methyl Isocyanide**: Methyl isocyanide has a lower boiling point because the dipole moment is less effective in creating strong intermolecular forces compared to methyl cyanide.

### Step 3: Comparing Dipole Moments
- **Dipole Moment of Methyl Cyanide**: The dipole moment is significant due to the electronegativity difference between carbon and nitrogen, which leads to a polar bond.
- **Dipole Moment of Methyl Isocyanide**: Although it also has a dipole moment, it is less than that of methyl cyanide because the nitrogen atom is bonded differently, which affects the overall molecular polarity.

### Step 4: Conclusion
- **Assertion**: Methyl cyanide has a higher boiling point than methyl isocyanide. This is true.
- **Reason**: The dipole moment of methyl cyanide is higher than that of methyl isocyanide. This is also true and provides a valid explanation for the assertion.

### Final Answer
Both the assertion and the reason are correct, and the reason correctly explains the assertion.