稀释时H+的物质的量n(H+)不变,根据C(H+)=n(H+)V V1=10ml ,C(H+)=10^-5 mol/L, pH=-lg10^-5=5 V2=0.1*V1=100ml, C(H+)=10^-6 mol/L pH=-lg10^-6=6 V3=0.01*V1=10000ml, C(H+)=10^-8 mol/L pH=-lg10^-8=8