This is the process of converting calcium carbide (CaC2) to butane (C4H10) through a series of chemical reactions:

CaC2 reacts with water to produce acetylene (C2H2):
CaC2 + 2H2O → C2H2 + Ca(OH)2

Acetylene (C2H2) then undergoes polymerization to form ethylene (C2H4):
2C2H2 → C2H4

Ethylene can then be further hydrogenated to form ethane (C2H6):
C2H4 + H2 → C2H6

Ethane can undergo chlorination to produce ethyl chloride (C2H5Cl):
C2H6 + Cl2 → C2H5Cl + HCl

Finally, ethyl chloride can undergo an elimination reaction to form butane (C4H10):
2C2H5Cl → C4H10 + HCl

Therefore, starting from calcium carbide, the series of reactions will lead to the formation of butane.