observer1 Posted October 31, 2022 Posted October 31, 2022 (edited) why is it when water is added to copper sulphate, the hydrogen does not displace the copper and form sulfuric acid? hydrogen is more reactive than copper in the reactivity series H2O + CuSO4 ---> H2SO4+ Cu? Edited October 31, 2022 by observer1
chenbeier Posted October 31, 2022 Posted October 31, 2022 No, CuSO4 dissociates to Cu(H2O)4 2+ ( blue colour) and SO4 2- ions, like all salts do if dissolved in water. NaCl => Na+ + Cl- as example. And your equation is wrong. H2O + CuSO4 ---> H2SO4+ Cu? You forget the oxygen from H2O H2O + CuSO4 <--- H2SO4+ CuO is a reaction what can take place.
sethoflagos Posted October 31, 2022 Posted October 31, 2022 (edited) 3 hours ago, observer1 said: why is it when water is added to copper sulphate, the hydrogen does not displace the copper and form sulfuric acid? hydrogen is more reactive than copper in the reactivity series H2O + CuSO4 ---> H2SO4+ Cu? Several reasons, but we can begin with entropy since you've overlooked a major consideration. The copper ions (actually Cu(H2O)6 2+) and sulphate ions have many more degrees of freedom floating around in the liquid phase than they do locked up in a solid crystalline phase - enough for that route to be thermodynamically favoured. Dissolving copper sulphate in water is an exothermic process anyway, due to the additional ligand bonds formed in the hydrated complex ion, so the Gibbs Free Energy arrow is only ever going to point in one direction (at normal ambient conditions at least). The extra bonding energy formed in such complex ions helps low reactivity elements (including platinum group metals) to leap up the reactivity index, so the latter is only a very approximate indicator, and often misleading if taken at face value. Edited October 31, 2022 by sethoflagos Clarification
John Cuthber Posted October 31, 2022 Posted October 31, 2022 (edited) 4 hours ago, observer1 said: H2O + CuSO4 ---> H2SO4+ Cu? because the correct reaction is H2 + CuSO4 ---> H2SO4+ Cu? And, in principle, that works. In practice you ned a catalyst like platinum. Edited October 31, 2022 by John Cuthber
chenbeier Posted October 31, 2022 Posted October 31, 2022 (edited) Yeah that is the correction of the observers1 question. Edited October 31, 2022 by chenbeier
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