Question

${Cl}^{-}$ is _____ (stronger/weaker) base than ${Br}^{-}$.

Answer 1

A stronger acid has a weak conjugate base and vice versa.

As order of acidity is $HI>HBr>HCl>HF$.

So, $C{l}^{-}$ is stronger base than $B{r}^{-}$.