AIIMS 2017 Chemistry Enthalpy Change MCQ Question
If at 298 K, the bond energies of C–H, C–C, C=C and H–H bonds are respectively 414, 347, 615 and 435 kJ mol⁻¹, the value of enthalpy change for the reaction:
at 298 K will be:
+250 kJ
–250 kJ
+125 kJ
–125 kJ
Correct Answer
Detailed Explanation
The calculation of the enthalpy change (ΔH°_reaction) involves subtracting the total bond energies (B.E) of the products from those of the reactants. In this case, the equation simplifies to ΔH°_reaction = [1050 kJ/mol] – [1175 kJ/mol], resulting in ΔH°_reaction = –125 kJ/mol, indicating an exothermic reaction where energy is released. Since options A, B, and D are not provided, they cannot be evaluated, but it is important to note that understanding bond energies and their contributions to reaction enthalpy is crucial for predicting reaction behavior in thermodynamics.
Found an issue with this question?