6.解：①V,=12.50mL.V=30.50-12.50=18.00mL ∴.V2V样品为NazC03+NaHCO, 2Na2C0%=2VIX CHC.MK2C03/2000/Ms =2×12.50X106.0X0.5000/(1.000×2000)×100%=66.25% NaHC0,%=(V2-V)·Ca·NaHC0k/1000/Ms×100% =(18.00-12.50)×0.5000×84.00/(1.00×1000)×100%=23.1%6.解：①V1=12.50mL, V2=30.50-12.50=18.00 mL ∴V2>V1 样品为Na2CO3 + NaHCO3 ②Na2CO3%=2V1×CHCL·MNa2CO3/2000/Ms =2×12.50×106.0×0.5000/(1.000×2000)×100%=66.25% NaHCO3%=(V2-V1)·CHCL·MNaHCO3/1000/Ms×100% =(18.00-12.50)×0.5000×84.00/(1.00×1000)×100%=23.1%