Write the balanced equation for reaction of a red oxidising agent using concentrated hydrochloric acid.

The solution is as follows:

      Zn (s) + 2 HCl (aq) $\to$ ZnCl₂(aq) + H_​2(g)

In the above reaction, HCl oxidises Zn into Zn²⁺ and H⁺ gets reduced to H₂.