What is the maximum buffer capacity of a 0.2M barbituric acid-sodium barbiturate buffer, and (b) at what pH does the maximum occur? (pKa of barbituric acid is 3.98)
a) 0.2 M, pH 3.98
b) 0.1 M, pH 3.98
c) 0.2 M, pH 7.00
d) 0.1 M, pH 7.40