EVERYDAY SCIENCE

Detailed explanation-1: -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.

Detailed explanation-2: -The reaction between hydrogen and oxygen is exothermic-it releases energy to the surroundings: hydrogen + oxygen → water 2H2 + O2 → 2H2O Fuel cells use the reaction between a fuel and oxygen to produce electrical energy.

Detailed explanation-3: -The decomposition of water requires 285.8 kJ energy per mole of water decomposed. It is an endothermic reaction. Heat is required to break the chemical bonds between hydrogen and oxygen molecules of water.

Detailed explanation-4: -Electrolysis is the process of using electricity to split water into hydrogen and oxygen.

Detailed explanation-5: -It involves the breaking of bonds. To break the bonding between atoms, energy is required. By providing energy in the form of heat or electricity, decomposition proceeds. As this reaction involves the breaking of the bond, energy is provided to them, so they are endothermic reactions.