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Chemistry · THERMODYNAMICS
हिन्दीFor the formation reaction \( \text{H}_2(g) + \text{Br}_2(l) \to 2\text{HBr}(g) \), the reaction enthalpy is \( \Delta_r H^\ominus = -72.8\text{ kJ mol}^{-1} \). What is the standard molar enthalpy of formation (\( \Delta_f H^\ominus \)) of \( \text{HBr}(g) \)?
Correct answer · Option 3
\( -36.4\text{ kJ mol}^{-1} \)
Explanation
Standard enthalpy of formation is defined for the formation of 1 mole of compound from its elements. Since 2 moles of HBr are formed, \( \Delta_f H^\ominus(\text{HBr}) = \frac{\Delta_r H^\ominus}{2} = \frac{-72.8}{2} = -36.4\text{ kJ mol}^{-1} \).
