题型示例一 :弱电解质的电离平衡【例 1】　 2 0℃时饱和H2 S溶液 1L ,其浓度为 0 .1mol·L- 1,其电离方程式为H2 SH++HS- ,HS-H++S2 - ,若要使该溶液的pH增大同时使c(S2 - )减小 ,可采用的措施是A .加入适量的水B .加入适量的NaOH固体C .通入适量的SO2D .加入适量的CuSO4 固体 Example 1: The ionization balance of the weak electrolyte [Example 1] The saturated H2S solution is 1L at 0°C, and its concentration is 0.1 mol·L-1. The ionization equation is H2 SH++HS-, HS-H+. +S2 - , to increase the pH of the solution while decreasing c(S2 - ), the measures that can be used are A. Add the appropriate amount of water B. Add the appropriate amount of NaOH solid C. Introduce the appropriate amount of SO2D. Appropriate amount of CuSO4 solid