89. Solving a chemistry problem

45. Compose electronic equations and arrange the coefficients in molecular equations for the following redox reactions:
Na2SO3 K2CrO7 H2SO4→Na2DO4 K2SO4 Cr2(SO4)3 H2O
CH3-CH2-CH2-CH2OH K2O2→CO2 H2O K2O
H2S H2SO4→S H2O

Indicate what type of redox reactions they belong to. Determine which substance is an oxidizing or reducing agent. which substance is oxidized and which is reduced during the reaction.