Answer:
The reaction of hex-3-yne with one equivalent of HCl Is an Anti addition, see in the drawing the major product.
Explanation:
The mechanism of the reaction proceeds through a carbocation, formed in the most substituted carbon of the triple bond, in this case it is indistinct because the triple bond is in the central carbons. Therefore, it is a regioselective reaction that follows Markovnikov's rule, adding the halogen to the more substituted carbon of the alkyne.
The anti addition consists in the addition of two substituents on opposite sides of a triple bond, which gives it greater stability.
