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Explain Born-Haber cycle for the fomation of 1 mole of sodium chloride crystal. |
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Answer» Solution :Step 1 : Sublimation of metallic sodium of gaseous sodium atom with ENTHALPY sublimation `=DeltaH_(s)` `Na(s) overset("sub lim ation")to Na(g), Delta= Delta H_(s)` Step : 1 Dissociation of molecules to chlorine atoms with enthaply of dissociation = `DeltaH_(d)(1)/(2)Cl_(2) (g) overset("Dissociation") to CL(g), DeltaH=DeltaH_(4)` Step-3 : Ionization of gaseous sodium with entahlpy of ionization `=DeltaH_(1)` `Na(g)overset("Ionization")to Na^(+)(g)` Step-4 : Addition of electron to gaseson chlorine atom with enthaply of electron affinity `Delta H_(Ed)Cl_((g))+e^(-)overset("Addition")toCl^(-)(g), DeltaH=DeltaH_(EA)` Step -5 Close packing of gaseous sodiumion and chloride ion the form lattice structure of NACL, with lattice chloride ion to form lattice structure of NaCl, Lattice ENERGY `U,NaCl^(+)(g)+Cl^(-)(g) to NaClDelta, Delta H=U` Step -6 But sum of all the energies will be equal to the heat of formation of one mole of sodium chloride form its reluctant i.e., `DeltaH_(f)` `Na(s)+(1)/(2)Cl_(2)(g) to NaCl(s), DeltaH=Deltaf_(f)` |
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