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Question

When HCl------> H+ + Cl- in aqueous medium, So, if we use ionization potential of H we get that the absorption of enery is 13.6 eV and a total of 3.8 eV is released according to electron affinity of Cl.. So, shouldnt the above process be endothermic?

Answer 1

You might at first think it could be endothermic, but you have to consider also the hydration process.  So, dissolving HCl in water involves not only ionization, but this is then followed by hydration.  The hydration process in combination with the ionization results in the total process being exothermic.