Chemistry · THERMODYNAMICS

Refer to the given enthalpy diagrams Fig. 5.10 (a) and Fig. 5.10 (b). Which of the following statements correctly differentiates the two diagrams?

1. A
   In (a), \( \Delta_r H < 0 \) (net heat evolved, exothermic); in (b), \( \Delta_r H > 0 \) (net heat absorbed, endothermic).
2. B
   Both (a) and (b) represent endothermic reactions at different temperatures.
3. C
   Diagram (a) represents an endothermic process whereas diagram (b) represents an exothermic process.
4. D
   In (a), \( H_{\text{products}} > H_{\text{reactants}} \) and heat is absorbed; in (b), \( H_{\text{products}} < H_{\text{reactants}} \) and heat is evolved.