Answer:
Si
Step-by-step explanation:
Dispersion force or London force is the force of attraction between two atoms or molecules in a substance in solid , liquid and gas . In gas , this force is minimum and in solid this force is maximum . In solid this force is maximum in metals in which this force forms metallic bond .
Among the given substances , Si , Sn , MgO , C₂₀H₄₂ are solid , so dispersion force will be high in them .
Among all as mentioned above , Si will have highest dispersion force . It is due to four covalent bond that bind two atoms of Si in solid silicon . Its three dimensional crystal structure consist of silicon atoms , all bound by four covalent bonds .