Write the reaction equation: Li2S ← S → H2S → SO2 → SO3 → Na2SO4 → BaSO4

1. Reaction of metallic lithium with sulfur when heated to 130 ° C.
S + 2Li = Li2S. (sulfur oxidation state = – 2).
2. Formation of hydrogen sulfide from simple substances.
S + H2 = H2S. (s. o. = – 2).
3. Combustion of hydrogen sulfide with the release of sulfur dioxide.
2H2S + 3O2 = 2H2O + 2SO2. (s. o. = + 4).
4. Oxidation of sulfur oxide (IV) to sulfur oxide (VI).
2SO2 + O2 = 2SO3. (s. o. = + 6).
5. Reaction of sulfur trioxide with alkali.
SO3 + 2NaOH = Na2SO4 + H2O. (s. o. = + 6).
6. Reaction of sodium sulfate exchange with barium chloride.
Na2SO4 + BaCl2 = 2NaCl + BaSO4. (s.o. = + 6).