浓度均为0.1 mol / L的①NaHCO₃、②Na₂CO₃、③NaCl、④NaHSO₄四种溶液，按pH值由小到大排列的顺序是

A．①②③④         B．④③①②          C．③④①②         D．②①④③

浓度均为0.1 mol / L的①NaHCO₃、②Na₂CO₃、③NaCl、④NaHSO₄四种溶液，按pH值由小到大排列的顺序是

1. A.
   ①②③④
2. B.
   ④③①②
3. C.
   ③④①②
4. D.
   ②①④③