Some amount of manganese dioxide was taken in a china dish and a few drops of hydrochloric acid were added to it. The contents were mixed well. After some time, a light pink coloured solid was obtained. The solid product in the given activity was obtained by-

Manganese dioxide reacts with hydrochloric acid to form manganese chloride, water, and chlorine gas. The chemical equation for the process is given below.

Water is a gas. Chlorine gas that will be formed during the process will escape into the atmosphere. Therefore, the pink colour that is obtained after the reaction was due to manganese chloride. It can easily be observed from the reaction that manganese chloride is formed by reduction of manganese oxide.