Question

Why are decomposition reaction mostly endothermic in nature

Answer 1

decomposition reaction is a reaction in which a given compound is broken down into two or more elements are compounds using some physical methods such as electricity sheets or sunlight so mostly it needs energy for The breakdown that's why decomposition reaction is mostly endothermic in nature

Answer 2

Decomposition reactions are the reactions in which a compound breakdowns into it two or more components.. Initially the components are bonded to each other by some kind of forces basically called bonds. these bonds can be electrovalent or covalent or any other kind of bonds depending upon the nature of the compound. to decompose the compound or to break those bonds into two components some amount of energy has to be supplied. that energy can be applied in any way or in any form like heat,electric field or by any other method.. when energy us supplied the atoms of components start vibrating and try to overcome the forces between them. When enough energy is met the break apart..
So almost all the decomposition reactions are mostly endothermic.