Question

1)Cr-->Cr2O3-->Cr2(SO4)3-->Cr(oh)3-->H2CrO4;
2)Cr(Oh)3-->KCrO2-->K2Cr2O7

Answer 1

1)
4Cr + 3O₂ = 2Cr₂O₃
Cr₂O₃ +3H₂SO₄(разб.) = Сr₂(SO₄)₃ + 3H₂O
Сr₂(SO₄)₃ + 6NaOH(разб) = 2Сr(OH)₃ (осадок) + 3Na₂SO₄
2Сr(OH)₃ + 3H₂O₂ = 2H₂CrO₄ + 4H₂O

2)
Сr(OH)₃ + KOH(cплавление) = KCrO₂ + 2H₂O
2KCrO₂ + 3H₂O₂ = K₂Cr₂O₇ + 3H₂O