Question

The pkb's of the bases A-, B-, C-, D- and X- are 10.72, 2.43, 5.67, 9.64 and 11.43 respectively. Arrange the following acids in order of increasing acid strength: HA, HB, HC, HD and HX

Answer 1

The pKb of the base is the characteristic of its strength. Low pKb means strong base. If a base are strong, that acid will be weak. For this question, stronger base is HB and weaker base is HX. Arrangement of acids from weak to strong:
HB → HC → HD → HA → HX