Question

Cr-CrCl3-Cr(OH)3-K9[Cr(OH)6]-Cr(SO4)3-Cr(OH)3-Cr2O3-CrO3-Na2CrO4-Na2Cr2O7

Answer 1

Cr--> Cr2O3-->Cr-->CrCl3-->Cr(OH)3-->Cr2(SO4)3 
4Cr + 3O2 = 2Cr2O3 
2Cr2O3 = 4Cr + 3O2 
2Cr+3Cl2=2CrCl3 
CrCl3+3NaOH=Cr(OH)3+3NaCl 
2Cr(OH)3+3H2SO4=Cr2(SO4)3+6H2O
Cr2(SO4)3 + 6KOH = 2Cr(OH)3 + 3K2SO4
2Cr(OH)3=Cr2O3+3H2O 
4СrO3 → 2Cr2O3 + 3O2↑
CrO3 + NaOH = H2O + Na2CrO4
Na2CrO4 + Н2SO4 = Na2Cr2O7 + Н2О + Na2SO4