The mean bond enthalpy of a C – F bond is 484 kJ mol⁻¹ - Scottish Highers Chemistry - Question 14 - 2016

To determine which process has a ΔH of approximately +1936 kJ mol⁻¹, we analyze the bond enthalpies and reaction process:

1. Calculate the total bond energy of CF₄:

   • The bond enthalpy for one C – F bond is 484 kJ mol⁻¹.
   • CF₄ contains four C – F bonds, so the total bond energy for breaking all these bonds is: $ext{Total bond energy} = 4 imes 484 ext{ kJ mol}^{-1} = 1936 ext{ kJ mol}^{-1}$

2. Identify the corresponding reaction:

   • The reaction that breaks all four C – F bonds leading to the formation of C and 4 fluorine atoms in the gas state is: $CF₄(g) → C(g) + 4F(g)$ This reaction requires breaking the four C – F bonds, thus costing +1936 kJ mol⁻¹.

Thus, the answer is B.