Question

Consider the following data on some weak acids and weak bases: acid base K. - K name formula name formula hydrofluoric acid HF 16.8 x 10-4 methylamine CH3NH2 4.4 x 10-4 ammonia NH3 1.8x10-5 nitrous acid HNO2 4.5 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 NaF choose one 0.1 M CH3NH3CI choose one 0.1 M KNO2 choose one 0.1 M NH4Br choose one x s ?

Answer 1

NaF 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

KNO2 is conjugate base of HNO2

So, its pH would be more than 7

NH4Br is conjugate acid of NH3

So, its pH would be less than 7

NH4Br is stronger acid as compared to NH4Br because Kb of CH3NH2 is more.

So, pH of NH4Br will be less than pH of CH3NH3Cl

NaF is stronger base as compared to KNO2 because Ka of HF is more.

So, pH of NaF will be more than pH of KNO2

Answer:

NaF: 4

CH3NH3Cl: 2

KNO2: 3

NH4Br: 1