Which of the following is a secondary alkyl halide?

To determine which of the provided compounds is a secondary alkyl halide, we first need to understand what a secondary alkyl halide is. A secondary alkyl halide is a compound in which a halogen atom (such as bromine) is attached to a carbon atom that is bonded to two other carbon atoms.

Now, let’s examine the options:

• CH₃CHBrCH₂ (option 1): In this compound, the carbon attached to bromine is bonded to one carbon (CH₂) and to two other carbon groups (CH₃ and CH₂), making it a secondary alkyl halide.
• CH₃CH₂CH₂Br (option 2): This is a primary alkyl halide because the carbon with bromine is attached to only one carbon chain.
• CH₃Br (option 3): This is also a primary alkyl halide because the carbon with bromine is united with only one carbon atom.
• CH₃CH₃CHBr (option 4): In this case, the carbon atom with bromine is bonded to two other carbon atoms, making it a tertiary alkyl halide.

Therefore, the only secondary alkyl halide from the options given is CH₃CHBrCH₂.