Assertion `:` Neopentene forms only one monosubstituted compound.
Reason `:` Neopentane has high bond energy

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 but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Explanation

To solve the question regarding neopentene and its monosubstituted compounds, we will analyze the assertion and reason provided step by step.

### Step 1: Understanding Neopentene Structure
Neopentene is an alkene with the formula C5H10. Its structure can be represented as:
```
CH3
|
CH3 - C - CH2 - CH3
|
CH3
```
This shows that neopentene has a central carbon atom bonded to four other carbon atoms (two of which are part of the same carbon chain).

### Step 2: Analyzing the Assertion
The assertion states that neopentene forms only one monosubstituted compound. A monosubstituted compound is formed when one hydrogen atom in the alkene is replaced by another atom or group (like Br in this case).

When we consider the substitution of neopentene:
- The central carbon atom has three identical methyl groups (CH3) and one methylene group (CH2).
- Substituting one hydrogen atom from the central carbon will yield a compound where the substituent can only attach to one of the equivalent positions.

Thus, the assertion is **true**: neopentene can only form one unique monosubstituted compound.

### Step 3: Analyzing the Reason
The reason states that neopentane has high bond energy. Neopentane (C5H12) is a saturated hydrocarbon, and its bond energies are generally high due to the stability of the C-H and C-C bonds.

However, the assertion about the formation of monosubstituted compounds does not directly depend on the bond energy of neopentane. The bond energy is a characteristic of the compound but does not influence the number of unique monosubstituted products formed.

Thus, the reason is **false**: while neopentane has high bond energy, this does not relate to the assertion about monosubstituted compounds.

### Conclusion
- The assertion is true: Neopentene forms only one monosubstituted compound.
- The reason is false: Neopentane's bond energy does not explain the assertion.

### Final Answer
The correct conclusion is that the assertion is true, and the reason is false.

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