13. Answer briefly IV

 

Electrolysis produces chlorine and hydrogenoxygen and hydrogenchlorine and nitrogenchlorine and oxygen gases, and sodium hydroxide from a concentrated  sodium chloridesodium oxychloride sodium sulphatesodium hydroxide solution known as brine. This is a important process in the industrial production of chlorine.

 

On heating, calcium carbonate provides calcium oxide and oxygen; then, it is an endothermicexothermiccombinationdecomposition reaction.