How many moles of conjugate base (Na2HPO4) are present in 40mL of .010M buffer at pH 7.5 vs at pH 6?
Buffer was made up of Na2HPO4 and NaH2PO4.
pH=pKa +log[A/HA]; pKa=7.2.... When I did the calculations I got the same amount as if it were in a 0.1M buffer at the same pH's so I think I'm doing something wrong.
Activity Coefficient for Phosphate Buffers: How would I calculate the predicted pH for Na2HPO4 and NaH2PO4? For hypothetical pH 6- we added 94mL of H2PO4 and 6mL of HPO4 (for a total of 100mL). But how would I calculate "actual pH"?
We measured at two different strengths, 0.1M and 0.01M. For HPO4 the correction factor for 0.1M-0.45 and 0.01-0.75 and for H2PO4 0.1-0.74 and 0.01-0.93.
I know it's a similar equation to the HH equation with the added log(A coeff/HA coeff) but I'm unsure how to proceed from there.
2 answers
Ignore the second post at 10:32, I'm going to post it as it's own question!
2 answers