Compare the coagulation power of HCl with KBr. Given the coagulation values are 30.8 and 138 respectively. 

The coagulation power is inversely proportional to coagulation value, the ratio of their coagulation power is 

$\frac{\text{ Coagulation power of }\mathrm{HCl}}{\text{ Coagulation power of }\mathrm{KBr}}$$=\frac{\text{ Coagulation value of }\mathrm{KBr}}{\text{ Coagulation value of }\mathrm{HCl}}$$=\frac{138}{30.8}=4.48$

$\therefore$HCl has 4.48 times greater coagulation power than KBr.