A.2 B.4 C.6 D.8
A.3 B.4 C.5 D.6
A、SnCl2+2FeCl3SnCl4+2FeCl2 B、Cl2+2NaOHNaClO+NaCl+H2O C、K2Cr2O7+2KOH2K2CrO4+H2O D、Zn+CuSO4ZnSO4+Cu