How can you prepare `Cl_2` from HCl and HCI from `Cl_2`? Write reactions only.

Explanation

HCl can be oxidised to `Cl_(2)` by a number of oxidising agent such as `MnO_(2), KMnO_(4), K_(2)Cr_(2)O_(7)`, etc.
`MnO_(2) + 4 HCl rarr MnCl_(2) + Cl_(2) + 2H_(2)O`
`Cl_(2)` can be reduced to HCl by its reaction with `H_(2)` in presence of diffused sunlight.
`H_(2) + Cl_(2) overset("Diffused sunlight")rarr 2HCl`