Consider the following data on some weak acids and weak bases:

acid Ka Base Kb
name Formula Name Formula
acetic acid HCH3CO2 =1.8 x10^5 Pyridine C5H5N =1.7x 10^9
hydrocyanic acid HCN =4.9 10^10 Aniline C6H5NH2 =4.3x 10^10

Use this data to rank the following solutions in order of increasing pH. In other words, select a '1'next to the solution that will have the lowest pH, a '2' next to the solution that will have the next lowest pH, and so on.

Solution pH

a. 0.1 M NaCl
b. 0.1 M C6H5NH3Cl
c. 0.1 M C5H5NHBr
d. 0.1 M NaCN