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The enthalpy changes for these reactions are given: 1/2 H2(g) + 1/2 O2(g) → OH(g); ΔH = 42.09 kJ mol⁻¹ H2(g) → 2H(g); ΔH = 435.89 kJ mol⁻¹ O2(g) → 2O(g); ΔH = 495.05 kJ mol⁻¹ Using this data, determine the O–H bond energy in the hydroxyl radical.

1. 223.18 kJ mol⁻¹
2. 423.38 kJ mol⁻¹
3. 513.28 kJ mol⁻¹
4. 113.38 kJ mol⁻¹

Correct answer: 423.38 kJ mol⁻¹

Solution

The O–H bond energy in the hydroxyl radical is calculated by considering the enthalpy changes of the given reactions. By applying Hess's law and combining the enthalpy values appropriately, we find that the bond energy corresponds to the correct option of 423.38 kJ mol⁻¹.

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