Chemistry - GOC Question with Solution | TestHub

The conjugate bases are $\mathrm{B}{\mathrm{r}}^{-}$ and ${\mathrm{I}}^{-}$, atoms in the same column, so size decides : ${\mathrm{I}}^{-}$ is larger and disperses the negative charge over a bigger volume, making it more stable. The more stable conjugate base means the stronger acid, so $\mathrm{HI}$ is more acidic.