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Examine the following claim and reasoning about an organic reaction: Claim: When 1-butene reacts with HBr in the presence of a peroxide, the product is 1-bromobutane. Reasoning: The reaction proceeds via formation of a primary carbon radical. Choose the correct option:

1. Both the claim and the reasoning are correct, and the reasoning correctly explains the claim
2. Both the claim and the reasoning are correct, but the reasoning does not correctly explain the claim
3. The claim is correct but the reasoning is incorrect
4. The claim is incorrect but the reasoning is correct

Correct answer: Both the claim and the reasoning are correct, and the reasoning correctly explains the claim

Solution

In the presence of peroxides, HBr adds via a free-radical mechanism (anti-Markovnikov). The bromine radical adds to the less substituted (terminal) carbon of 1-butene, generating the more stable secondary radical at C2, and then H adds to C2, giving 1-bromobutane. The claim is correct; however the reasoning states a primary radical is formed, which is incorrect — a secondary radical intermediate is formed.

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