# Why do acetylene and chlorine react to yield carbon and HCl, but acetylene and bromine react less intensely?

In the famous "underwater fireworks" reaction we get

$$\ce{C2H2 + Cl2 -> 2C + 2HCl}$$

On the other hand, when we react acetylene with bromine, we get

$$\ce{CH#CH + Br2 -> CHBr=CHBr}$$ $$\ce{CHBr#CHBr + Br2 -> CHBr2-CHBr2}$$

Why don't we get carbon and HBr? Or do we get it?