The chemical reaction shown above involves the formation of various products through a series of steps. The reaction starts with the combination of methane $CH4$ and chlorine gas $Cl2$ to form an intermediate product $x1$, which subsequently reacts with sodium $Na$ to produce another intermediate product $x2$. This intermediate product then reacts with bromine gas $Br2$ to form another intermediate product $x3$, which finally reacts with sodium $Na$ to produce the final product $x4$.

Overall, the reaction can be summarized as follows:
CH4 + Cl2 -> x1
x1 + Na -> x2
x2 + Br2 -> x3
x3 + Na -> x4

Each step in the reaction involves the formation of an intermediate product, which eventually leads to the formation of the final product. The specific identities of the intermediate products $x1,x2,x3$ and the final product $x4$ would depend on the specific reaction conditions and the relative quantities of the reactants involved.