Answer:
B.4.75
Step-by-step explanation:
Buffer solutions are the solutions which can resist the change in the pH up to some extent. They are the solutions of either weak acid and conjugate base of it or weak base and conjugate acid of it.
The pH of a buffer solution can be measured by the equation known as Henderson–Hasselbalch equation.
pH=pKa+log[base]/[acid]
A good buffer that buffer which has its acid's pKa within one pH unit of desired experimental conditions.
Thus, desired pH = 5.3
Preferable pKa = 4.3 - 6.3
Answer - B. 4.75