If degree of unsaturation is three, then a compound shows :

Options

A. one triple bond and one double bond
B. one double bond and two rings
C. one ring and two double bonds
D. all of these are correct

Answer

To solve the question regarding the degree of unsaturation being three, we can follow these steps:

### Step 1: Understand the Concept of Degree of Unsaturation
The degree of unsaturation (DU) indicates the number of rings and/or multiple bonds (double or triple) present in a compound. Each degree of unsaturation corresponds to either a ring or a double bond, while a triple bond counts as two degrees of unsaturation.

### Step 2: Use the Formula for Degree of Unsaturation
The formula for calculating the degree of unsaturation is:
\[ \text{Degree of Unsaturation} = \frac{C + 2 + n - x - H}{2} \]
Where:
- \( C \) = number of carbon atoms
- \( n \) = number of nitrogen atoms
- \( x \) = number of halogens
- \( H \) = number of hydrogen atoms

### Step 3: Analyze the Given Degree of Unsaturation
Here, we are given that the degree of unsaturation is 3. This means that the compound can have various combinations of rings and multiple bonds.

### Step 4: List Possible Combinations
With a degree of unsaturation of 3, the compound can exhibit the following combinations:
1. Three rings
2. Two rings and one double bond
3. One ring and two double bonds
4. One ring and one triple bond
5. One double bond and one triple bond
6. Three double bonds

### Step 5: Evaluate the Options
Given the combinations listed above, we can conclude that if a compound has a degree of unsaturation of 3, it can show:
- 1 triple bond and 1 double bond
- 1 double bond and 2 rings
- 1 ring and 2 double bonds
- And other combinations as mentioned.

### Step 6: Conclusion
Since all combinations mentioned are valid for a degree of unsaturation of 3, the correct answer to the question is that the compound can show all of these possibilities.

### Final Answer
The compound can show all of the following: 1 triple bond and 1 double bond, 1 double bond and 2 rings, 1 ring and 2 double bonds, etc.

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