In the reaction $$MnO_2 + 4HCl → MnCl_2 + 2H_2O + Cl_2$$, what is being reduced?

Correct option is D

Correct option: (d), Manganese (Mn)

In the given reaction:

$$MnO_2+4HCL\rightarrow MnCl_2+2H_2O+Cl_2$$ 

Reduction is the gain of electrons, which causes the oxidation state of an element to decrease.

Let's analyze the oxidation states:

1. ​Manganese (Mn) in $$MnO_2$$ The oxidation state of oxygen is -2, and there are 2 oxygen atoms. Therefore, the oxidation state of Mn must be +4 to balance the charge (since the overall charge on the molecule is neutral).
2. Manganese (Mn) in  ​The oxidation state of chlorine is -1, and there are 2 chlorines. The total charge from chlorine is -2, so the oxidation state of Mn must be +2.$$MnCl_2$$ 

Since the oxidation state of Mn decreases from +4 in $\text{MnO}$ to +2 in $\text{MnCl}$, Mn is reduced.

On the other hand, chlorine (Cl) in HCl starts as -1 and ends up as 0 in Cl₂ (molecular chlorine), indicating that chlorine is oxidized (losing electrons).