Question

Part A

Which of the following buffer systems would be the best choice to create a buffer with pH = 9.10?
HF/KF
HNO2/KNO2
NH3/NH4Cl (ANSWER)
HClO/KClO

Part B For the best system, calculate the ratio of the masses of the buffer components required to make the buffer. Express your answer using two significant figures.

Answer 1

Buffer solution with a pH of 9.10 means the buffer solution is basic buffer.So, among the given compounds

a) HF/KF
b) HNO2/KNO2
c) NH3/NH4Cl
d) HClO/KClO

the best choice is NH3/ NH4Cl.

pH + pOH = 14

pOH = 14 - 9.10

        = 4.9

pOH = pKb + log(salt/base)

4.9 = 4.75 + log(salt/base)

[salt/base] = 10^-0.15

                   = 0.808