What is the ratio of concentration of NaH2PO4- and Na2HPO4- in phosphate buffer at pH 7.4?:scared:

Thanks

Anyone???:(

use Henderson-Hasselbalch equation.

pH=pKa + log (Base/acid)
you have to use pKa 7.21(pka1=2.12, pKa2=7.21, pKa3=12.32) because it is closed to your pH.

7.40= 7.21+ log(HPO4-2/H2PO4-)

log(HPO4-2/H2PO4-)=0.19

(HPO4-2/H2PO4-)=10^0.19
= 1.5
don't worry about this kind of questions my persian firend. ;)
good luck