This section contains assertion and reason type questions. Each question has 4 choice (1), (2),(3), and (4), out of which only one is correct.
Assertion (A) Vinylacetylene is but-1-ene – 3 – yne.
Reason ( R) Double bond is preferred over triple bond while naming the organic compound.

Options

A. Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion
B. Both Assertion and Reason are correct but reason is not the correct explanation of Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

Answer

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

### Step 1: Analyze the Assertion
**Assertion (A): Vinylacetylene is but-1-ene-3-yne.**

1. **Identify Vinylacetylene**: Vinylacetylene is a compound that contains both a vinyl group (which is a carbon-carbon double bond) and an acetylene group (which is a carbon-carbon triple bond).
2. **Determine the Structure**: The structure of vinylacetylene can be represented as follows:
- The longest carbon chain consists of four carbon atoms.
- The first carbon has a double bond (alkene), and the third carbon has a triple bond (alkyne).
3. **IUPAC Naming**: According to IUPAC nomenclature:
- The double bond is indicated by “-ene” and the triple bond by “-yne”.
- Since there is both a double bond and a triple bond, we must prioritize the double bond when numbering the carbon chain.
- Thus, the correct name for vinylacetylene is indeed but-1-ene-3-yne.

**Conclusion for Assertion**: The assertion is correct.

### Step 2: Analyze the Reason
**Reason (R): Double bond is preferred over triple bond while naming the organic compound.**

1. **Understanding Priority in Naming**: In organic nomenclature, when both double and triple bonds are present, the double bond is given higher priority.
2. **Lower Numbering Rule**: The lowest possible number is assigned to the double bond when numbering the carbon chain. This is known as the lower number rule.
3. **Explanation of Preference**: The reason states that the double bond is preferred over the triple bond, which aligns with the IUPAC naming conventions.

**Conclusion for Reason**: The reason is also correct and provides a valid explanation for the assertion.

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

### Answer Choice
The correct answer is: **(1)** Both A and R are correct, and R is the correct explanation for A.

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