α1=0.001/0.1=1%=（Ka/[HA]）^1/2α2=（Ka/0.5[HA]）^1/2α2/α1=[（Ka/0.5[HA]）^1/2]/[（Ka/[HA]）^1/2]=2^1/2α2=2^1/2×α1=2^1/2×1%=1.414%PH=-lg（0.05×1.414%）=3.15
