Transform the following reactions into equations and balance them :
(i) Barium chloride reacts with dilute sulphuric acid to produce hydrochloric acid and a precipitate of barium sulphate.
(ii) Aluminium metal reacts with copper(II) chloride to form aluminium chloride and copper .
(iii) Chlorine gas reacts with potassium iodide to form iodine and potassium chloride.
(iv) Manganese dioxide reacts with concentrated hydrochloric acid to form manganese(II) chloride , water and chlorine gas .