A.0.03 mol•L -1的HCl溶液中c(H +)=c(HCl)=0.03 mol/L;
B.0.02 mol•L -1H 2SO 4溶液中c(H +)=2c(H 2SO 4)=0.04mol/L;
C.pH=2的HCl溶液中c(H +)=10 -2mol/L=0.01mol/L;
D.0.05 mol•L -1的HNO 3溶液中c(H +)=c(HNO 3)=0.05 mol/L;
所以氢离子浓度最小的是C,
故选:C.
A.0.03 mol•L -1的HCl溶液中c(H +)=c(HCl)=0.03 mol/L;
B.0.02 mol•L -1H 2SO 4溶液中c(H +)=2c(H 2SO 4)=0.04mol/L;
C.pH=2的HCl溶液中c(H +)=10 -2mol/L=0.01mol/L;
D.0.05 mol•L -1的HNO 3溶液中c(H +)=c(HNO 3)=0.05 mol/L;
所以氢离子浓度最小的是C,
故选:C.