Q.
Calculate bond enthalpy (in kJmol−1 ) of C−Cl in CCl4(g) from the following
Data: ΔvapHCCl4∘=30.5kJmolΔfH(CCl4,l)∘=−135.5kJ/mole ΔaH∘(C)=715kJ/mol (i.e. enthalpy of atomisation) ΔaHCl2∘=242kJ/mole
C(s)+2Cl2(g)→CCl4(ℓ)ΔH=−135.5KJ/moleCCl4(ℓ)→CCl4(g)ΔH=30.5KJ/ mole C(s)+2Cl2(g)⟶CCl4(g)ΔH=−105KJ/ mole 715+2×242−4×x=−105 x=326KJ/ mole
i.e. x=B.E. of C−Cl in CCl4(g)