Higher 
 the Ka : higher the acidity. 
 Higher 
 the Kb : higher the basity.
 
 Higher  the pKa : lower the acidity. 
 Higher  the pKb : lower the basity.
 Which one is weaker acid?
 HNO2    ;   Ka= 4.0 x 10-4.    pKa= 3.39
 HOCl2   ;   Ka= 1.2 x 10-2.    pKa= 1.92 
 HOCl     ;  Ka= 3.5 x 10-8.    pKa= 7.46
 HCN      ;  Ka= 4.9 x 10-10. 
 pKa= 9.31