What is the degree of unsaturation of cubane?

Answer

To find the degree of unsaturation of cubane (C8H8), we can follow these steps:

### Step 1: Understand the Formula for Degree of Unsaturation
The degree of unsaturation (DU) can be calculated using the formula:
\[ DU = \frac{(2C + 2 + N - H - X)}{2} \]
where:
- \(C\) = number of carbon atoms
- \(H\) = number of hydrogen atoms
- \(N\) = number of nitrogen atoms (if any)
- \(X\) = number of halogen atoms (F, Cl, Br, I)

### Step 2: Identify the Number of Atoms in Cubane
For cubane, the molecular formula is C8H8. Therefore:
- \(C = 8\)
- \(H = 8\)
- \(N = 0\) (no nitrogen)
- \(X = 0\) (no halogens)

### Step 3: Substitute the Values into the Formula
Now, substitute the values into the degree of unsaturation formula:
\[ DU = \frac{(2(8) + 2 + 0 - 8 - 0)}{2} \]

### Step 4: Simplify the Equation
Calculate the values inside the parentheses:
\[ DU = \frac{(16 + 2 - 8)}{2} \]
\[ DU = \frac{10}{2} \]
\[ DU = 5 \]

### Conclusion
The degree of unsaturation of cubane is 5.

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