Buffer solutions are supposed to be made of weak acid and its conjugate base or weak base and its conjugate acid. BUT: weak base has a strong conjugate acid and vice versa. So I could make a buffer solution from Cl- ions (really weak base) and HCl (conjugate acid). But that's the same as making buffer from HCl (strong acid) and Cl- (conjugate base) which against the rule we had in the first place, isn't it. This contradiction makes understanding buffer solutions quite hard. Please explain!