Answer:
A spontaneous process is capable of proceeding in a given direction without needing to be driven by an outside source of energy.
A spontaneous process is one that occurs on its own, without any energy input from the outside. For example, a ball will roll down an incline; water will flow downhill; ice will melt into water; radioisotopes will decay; and iron will rust. No intervention is required because these processes are thermodynamically favorable. In other words, the initial energy is higher than the final energy.
An endergonic reaction (also called a nonspontaneous reaction or an unfavorable reaction) is a chemical reaction in which the standard change in free energy is positive, and energy is absorbed.
A process which can neither take place by itself nor by initiation is called a non spontaneous process.
For Example.
1) Flow of water up a hill.
2) Flow of heat from cold body to a hot body. 3) Diffusion of gas from low pressure to a high pressure.
