[MJF]

CH3-C≡C-CH3   HBR (excess)         ?
                         

I understand that this is an addition reaction with the use of the strong acid, HBr and that H and Br will be added to the reaction. The question is where exactly? The way our professor teaches us is that, in this case, the C with more H attached to it will receive the extra H, while the C with the least amount of H attached will receive the Br. The problem I have is that both Carbons have no H attached, just R groups.

After going over the problem, I checked the answer and it was: CH3-CHBR-CHBR-CH3. Can anyone help me with this?

[discodermolide]

This is a reaction of the triple bond with HBr.

Do you know how HBr adds to C=C bonds? If so try and apply it to the triple bond case.