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Explain the steps involved in Born Haber cycle for the formation of NaCl. |
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Answer» Solution :Step 1: Sublimation of metalic sodium of gaseous sodium ATOM with ENTHALPY of sublimation `=DeltaH_(s)` `Na(s)overset("sublimation")(to)Na(g),DeltaH=DeltaH_(s)` Step 2:Dissociation of molecule of chlorine to chlorine atoms with enthalpy of dissociation `=DeltaH_(d)` `1/2Cl_(2)(g)overset("Dissociation")(to)Cl(g),DeltaH=DeltaH_(d)` Step 3: IONIZATION of gaseous sodium with enthalpy of ionization `=DeltaH_(i)` `Na(g)overset("ionization")(to)Na^(+)(g)` Step 4: Addition of electron to gaseous chlorine atom with enthalpy of electron affinity `=DeltaH_(Ea)` `Cl_((g))+e^(-)overset("addition of" e^(-))(to) Cl^(-1)(g),DeltaH=DeltaH_(Ea)` Step -5: Close packing of gaseous sodium ion and chloride ion to FORM lattice structure of NaCl, with lattice chloride ion to form lattice structure of NaCl, with Lattice energy `=U, NaCl^(+)(g)+Cl^(-1)(g)toNaClDelta, DeltaH=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//2Cl_(2)(g)toNaCl(s),DeltaH=DeltaH_(f)` |
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