Question

convert ethane to butane

Answer 1

This conversion is a two steps reaction, 1-photochemical halogenation of ethane, 2- wurtz reaction of ethyl chloride.
CH3-CH3 + Cl2 ------- sun light -------> CH3-CH2-Cl + HCl
2CH3-CH2-Cl + 2Na ---------anhydrous ether -------> CH3-CH2-CH2-CH3 + 2NaCl
Hope it helps