${\mathrm{KMnO}}_4+\mathrm{HCl}⟶{\mathrm{H}}_2\mathrm{O}+\mathrm{X}\left(\mathrm{g}\right),\mathrm{X}$ is a:

(Acidified)

X is chlorine which is greenish-yellow gas. It belongs to the group of elements in the periodic table known as halogens and has an atomic number of 17. 

The reaction between potassium permanganate and hydrochloric acid produces Potassium chloride (KCl), manganese chloride $\left({\mathrm{MnCl}}_2\right)$, water $\left({\mathrm{H}}_2\mathrm{O}\right)$, and chlorine gas .

${\mathrm{KMnO}}_4+\mathrm{HCl}⟶{\mathrm{H}}_2\mathrm{O}+\mathrm{KCl} +{\mathrm{MnCl}}_2+{\mathrm{Cl}}_2\left(\mathrm{g}\right)$