pH=3的盐酸中的C(H+)=0.001mol/LPH=12的NaOH溶液C(OH-)=0.01mol/L假设溶液的体积为V升,混合后溶液的体积为2V.有：C(OH-)=(0.01V-0.001V)/2V=0.0045mol/LC(H+)=10^-14/0.0045=2.22*10^-12PH=-lgc(H+)=-lg(2.22*10^-12...