Draw the mechanism for the following reaction:

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Step 1: Analyze the reactants and reagents. The starting material is 1-pentyne (CH₃CH₂CH₂C≡CH), and the reaction involves bromine (Br₂) in water (H₂O). This suggests a halohydration reaction mechanism, where bromine adds across the triple bond in the presence of water.

Step 2: Initiate the reaction mechanism. Bromine (Br₂) acts as an electrophile and is polarized due to the electron density of the triple bond. The π-electrons of the alkyne attack Br₂, forming a cyclic bromonium ion intermediate.

Step 3: Water (H₂O) acts as a nucleophile and attacks the more substituted carbon of the bromonium ion, leading to the opening of the cyclic intermediate. This results in the addition of a hydroxyl group (-OH) to the more substituted carbon and a bromine atom to the less substituted carbon.

Step 4: The hydroxyl group undergoes tautomerization. The enol intermediate (CH₃CH₂CH₂C(OH)=CHBr) rearranges to form a more stable keto form (CH₃CH₂CH₂C(O)CH₂Br). This keto-enol tautomerization is facilitated by the acidic or basic conditions in the reaction medium.

Step 5: Verify the final product. The reaction yields 2-bromo-2-pentanone (CH₃CH₂CH₂C(O)CH₂Br), where the bromine atom and the carbonyl group are attached to adjacent carbons. This is consistent with the halohydration mechanism and the given product structure.

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