Assertion: tert-butylbromide undergoes `S_(N)1` nucleophilic substitution readily than n-butyl bromide.
Reason: It proceeds by the formation of stable carbocation.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.

Answer

To solve the question regarding the assertion and reason about tert-butyl bromide and n-butyl bromide undergoing nucleophilic substitution reactions, we can break it down into a step-by-step explanation.

### Step 1: Understanding the Compounds
- **Tert-butyl bromide** (C4H9Br) has the structure (CH3)3C-Br. It is a tertiary alkyl halide.
- **n-butyl bromide** (C4H9Br) has the structure CH3-CH2-CH2-CH2-Br. It is a primary alkyl halide.

### Step 2: Mechanism of SN1 Reaction
- The **SN1 mechanism** involves two steps:
1. Formation of a carbocation by the departure of the leaving group (Br in this case).
2. Nucleophilic attack on the carbocation.

### Step 3: Carbocation Stability
- **Tertiary carbocations** (like that formed from tert-butyl bromide) are more stable than **primary carbocations** (like that formed from n-butyl bromide).
- The stability of carbocations increases with the number of alkyl groups attached to the positively charged carbon. Tertiary carbocations are stabilized by hyperconjugation and inductive effects from surrounding alkyl groups.

### Step 4: Rate of Reaction
- Since the rate of an SN1 reaction depends on the stability of the carbocation formed, tert-butyl bromide, which forms a stable tertiary carbocation, will react faster than n-butyl bromide, which forms a less stable primary carbocation.

### Step 5: Conclusion
- Therefore, the assertion that tert-butyl bromide undergoes SN1 nucleophilic substitution more readily than n-butyl bromide is true.
- The reason that it proceeds by the formation of a stable carbocation is also true.

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

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