Question

Which of the four solutions is the best buffer against addition of acid or base?
a.na2hpo4
b.na2hpo4 + nah2po4
c.nah2po4
d.h2o submit for grading save and finish later?

Answer 1

b. Na2HPO4 + NaH2PO4.

A buffer is a solution of a weak acid and its conjugate base. The weak acid is H2PO4^(-) and its conjugate base is HPO4^(2-).

All the other options are incorrect because they consist of only a single component.