Identify the oxidising agent, reducing agent, substance oxidised and substance reduced in the following reactions.
` MnO_2 + 4HCl to MnCl_2 + Cl_2 + 2H_2O`

Explanation

As it is clear, manganese decrease its oxidation number from +4 to +2. Hence, `MnO_2` gets reduced and it is an oxidising agent. Chlorine atom in HCl increases its oxidation number from -1 to 0. Thus, HCl gets oxidised and it is reducing agent.