Question

配制K2HPO4 /NaH2PO4电泳缓冲液时,取0.3mol/L K2HPO4 300ml 和0.7mol/L NaH

Answer 1

求pH?

H2PO4- HPO42- + H+

Ka2(H3PO4)=10^(-7.21)=c(H+)*c(HPO42-)/c(H2PO4-)

=c(H+)*n(HPO42-)/n(H2PO4-)

=c(H+)*(0.3mol/L*0.3L)/(0.7mol/L*0.7L)

c(H+)=10^-7.21* 0.49/0.09=3.36*10^-7

pH=-lgc(H+)=-lg3.36*10^-7=6.47