3 любых ионных реакций

K2Cr2O7+4H2SO4+3H2O2=K2SO4+

+Cr2(SO4)3+7H2O+3O2↑

Cr2O7{2-} + 8H{+} + 3H2O2=2Cr{3+} + +7H2O + 3O2↑

Hg(NO3)2+2KOH=HgO+H2O+2KNO3

Hg{2+} + OH{-} = HgO↓ + H2O

CoCl2+Pb(NO3)2=Co(NO3)2+PbCl2↓

Pb{2+} + 2Cl{-} = PbCl2↓