I don't see a question here. I assume you want directions for preparing the buffer. Let's say you want 1 L of the buffer.
pH = pKa + log (base)/(acid)
7.40 = pK2 + log (base)/(0.0100)
You will need to look up pK2 for H3PO4. solve the equation for (base).
Knowing you want 1 L of solution, you want mols = M x L = ?
Now you know mols NaH2PO4(the acid) and mols NaHPO4(the base). Calculate grams from g = mols x molar mass.
Weigh the amounts of acid and base and dissolve enough water to make 1 L.
The pH of human blood needs to be between 7.35 and 7.45. You want to prepare a buffer
solution that gives a pH of 7.40. You decide to use a sodium phosphate buffer: the acid is H2PO−4 and the conjugate base is HPO2−
4. You want the concentration of the acid to be 0.0100 M.
2 answers
I'm sorry the full question was:
1. If the initial H2PO−
4
concentration is 0.0100 M, what is the initial concentration of
HPO2−
4
that will give a pH of 7.40?
2. What is the maximum molarity of acid that this buffer can neutralize without the pH
dropping below 7.35?
3. What is the maximum molarity of base that this buffer can neutralize without the pH
going above 7.45?
1. If the initial H2PO−
4
concentration is 0.0100 M, what is the initial concentration of
HPO2−
4
that will give a pH of 7.40?
2. What is the maximum molarity of acid that this buffer can neutralize without the pH
dropping below 7.35?
3. What is the maximum molarity of base that this buffer can neutralize without the pH
going above 7.45?