Write the reaction equation: SiO2- Si- Ca2Si- SiH4- SiO2- Si

1) SiO2 + 2C = Si + 2CO (when silicon dioxide interacts with carbon, silicon and carbon monoxide are formed);

2) Si + 2Ca = Ca2Si (when silicon interacts with calcium, calcium silicide is formed);

3) Ca2Si + 4HCl = 2CaCl2 + SiH4 (when calcium silicide interacts with hydrochloric acid, calcium chloride and monosilane are formed);

4) SiH4 + 2H2O = SiO2 + 4H2 (when monosilane interacts with water, silicon dioxide and hydrogen are formed);

5) SiO2 + 2Mg = Si + 2MgO (when silicon dioxide interacts with magnesium, silicon and magnesium oxide are formed).