All chemical reactions are reversible in principle.
Reactions proceed until equilibruim is reached.
Equilibruim is a dynamic state where no net change in concentration of reactants occurs. If reaction products contain less free energy than reactants, reaction is spontaneous. Energy is released in an exergonic reaction. Endergonic Reacton Energy must be added for this reaction to proceed The change in free energy is positive Non-spontaneous or endergonic reaction. All rights reserved.