Question

Consider the following data on some weak acids and weak bases: acid K. name formula name base Kg formula hydroxylamine HONH, 1.1 10-8 hydrocyanic acid lic acid | HCN | 49 x 10-10 | HCN hydrofluoric acid HF 6.8 x 10-4 methylamine 1.4 x 10-4 Use this data to rank the following solutions in order of increasing pH. In other words, select a 'l' 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 0.1 M KI choose one 0.1 M KF choose one 0.1 M CH3NH3CI choose one 0.1 M NaCN choose one

Answer 1

KI is neutral salt.

So, its pH would be 7

KF is conjugate base of HF

So, its pH would be more than 7

CH3NH3Cl is conjugate acid of CH3NH2

So, its pH would be less than 7

NaCN is conjugate base of HCN

So, its pH would be more than 7

NaCN is stronger base as compared to KF because Ka of HF is more.

So, pH of NaCN will be more than pH of KF

Answer:

KI: 2

KF: 3

CH3NH3Cl: 1

NaCN: 4