What is the product when an alkene is treated with Br2?

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Adding bromine to an alkene is an electrophilic addition that converts the carbon–carbon double bond into a single bond with bromine atoms added across the bond. The mechanism involves formation of a bromonium ion, then opening by bromide from the opposite side, giving anti addition. The overall product is a 1,2-dibromoalkane: two bromine atoms attached to the two adjacent carbons of the original double bond. This explains why the product is dibromoalkane. A haloalkane would come from replacing a hydrogen with bromine on an alkane, not from this addition to a double bond, and an alcohol would require hydration or oxidation rather than simple Br2 addition.