Question

Electrolysis of water is an endothermic or exothermic reaction? And why?

Answer 1

Electrolysis of water is an endothermic reaction that is it absorbs energy . In this case for the reaction to occur, electricity is absorbed hence it is endothermic.

Answer 2

Electrolysis of water is an 'endothermic reaction'. During electrolysis, heat is given to the water which gets absorbed by water to give oxygen and hydrogen and so the reaction is an endothermic reaction.  

EXPLANATION:

An endothermic reaction is the one that absorbs or uses heat from its surroundings. Water for electrolysis needs heat i.e. heat is absorbed and not given out which makes electrolysis an endothermic reaction. Endothermic reaction can be a chemical process or a physical process.