5Na2SO3----2KMnO4 n(KMno4)=a mol/L*b*10-3L=0.001ab mol 5 2 Xmol 0.001ab mol X=0.0025ab mol m(Na2SO3)=126*0.0025ab g=0.315ab gNa2So3(含Na2So4)的纯度: (0.315ab g*250/25)/W g×100%=(315ab/W)%
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