Name the substance oxidized and reduced in the given reaction:

HCl is oxidized, and MnO₂ is reduced.

HCl is oxidized to chlorine as hydrogen is removed and removal of hydrogen is oxidation.

MnO₂ is reduced to MnCl₂ as oxygen is removed and removal of oxygen is called reduction. So we can say HCl is oxidized to chlorine and MnO₂ is reduced to MnCl₂.