Question

pH=3盐酸加水到原来的10^6倍,pH =

Answer 1

稀释前c(H+)=10^-3 mol/L

稀释后c(H+)=10^(-3-6)mol/L==10^-9 mol/L

H2O H+ + OH-

起始 10^-9 0

平衡 10^-9 +x x

(10^-9 +x)* x=Kw=1.0*10^-14

解得: x=9.95*10^-8mol/L

[H+]=(9.95*10^-8+10^-9)=1.005*10^-7 mol/L>10^-7mol/L ,可见溶液还是酸性

PH=-lg1.005*10^-7=6.99 约为7