Explain how, mercury is extracted from its sulphide ore (cinnabar). Give equations of the reactions involved.
Cinnabar is a sulphide ore of mercury. The name of the compound present in the cinnabar ore is mercury (II) sulphide. Its chemical formula is HgS. Mercury is a less reactive metal and it can be extracted from its sulphide ore cinnabar by heating it in air alone.
1. It is first heated in the presence of surplus air (roasting process). This converts mercury (II) sulphide to mercury (II) oxide.
Mercury (II) oxide, so formed, is heated to around 300°C and it gets reduced to mercury metal.