Final answer:
The product formed when 1-butyne reacts with excess bromine in CCl4 is 1,1,2,2-tetrabromobutane, which occurs through a halogen addition reaction where all the carbon atoms from the original triple bond are saturated with bromine atoms.
Step-by-step explanation:
When 1-butyne is treated with excess Br2 in CCl4, the product formed is 1,1,2,2-tetrabromobutane.
1-butyne is an alkyne with a triple bond between the first and second carbon atoms. In the presence of excess bromine, the triple bond reacts to form a tetra-substituted alkane. Each carbon atom involved in the triple bond gets two bromine atoms attached - one bromine atom adds to each carbon in the initial step to form a 1,2-dibromobutene, then another addition of bromine happens to achieve the final product, 1,1,2,2-tetrabromobutane, where both carbons previously involved in the triple bond are now each bonded to two bromine atoms.