Identify an energy diagram showing the energy of the reaction as a function of the progress of the reaction.

a potential energy diagram of a chemical reaction shows the net change in energy as reactants change into products.

the net change in energy corresponds to the change in gibb's free energy (delta g) for a reaction. this also relates to the change in  enthalpy  (delta h) for a reaction. the gain or loss of energy by the reaction from or to the surroundings indicates whether a reaction is endothermic or exothermic.

an endothermic reaction involves a net increase in potential energy as reactants change into products. energy is gained by the system from the surroundings. so, delta h is positive. this type of reaction will feel cold, or absorb heat.

an exothermic reaction involves a net decrease, so dealt h is negative. this type of reaction will feel warm or give of heat.

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach