Select the correct options for the following statements.

$1.$ $\mathrm{C}{\mathrm{l}}_2\mathrm{O}$ and $\mathrm{C}\mathrm{l}{\mathrm{O}}_2$ are used as bleaching agents.

$2.$ $\mathrm{O}\mathrm{C}{\mathrm{l}}^{-}$ salts are used as detergents.

$3.$ $\mathrm{O}\mathrm{C}{\mathrm{l}}^{-}$ disproportionates in alkaline medium.

$4.$ $\mathrm{B}\mathrm{r}{\mathrm{O}}_3^{-}$ is oxidized in acidic medium.