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A:2Al+2NaOH+2H2O=2NaAlO2+3H2↑
B:KMnO4+HCOOK+KOH=2K2MnO4+CO2↑+H2O
C:MnO2+4HCl(浓) MnCl2+Cl2↑+2H2O
D:K2Cr2O7+6FeSO4+7H2SO4=Cr2(SO4)3+3Fe2(SO4)3+K2SO4+7H2O