QAIPMT-2003-Ch-2685: NEET 2003 Chemistry - Class 11 AIPMT-2003-Ch-2685 Solution: For which one of the following equations is \( H^ _{react}\)…

Heat of formation, _ H o f of a substance is the amount of heat absorbed or released when one mole of this substance is formed directly from its constituent elements. In option (a), one mole of XeF 4 is formed from its constituent elements i.e., Xe and F 2 thus, the equation has equal value of _ H o r and _ H o f . In option (b), the constituent atoms should be carbon and oxygen only but the reactant used is CO thus, _ H o r � _ H o f In option (c), the reactant used is O 3 which is again not in its element form thus, _ H o r � _ H o f In option (d), two products are formed thus _ H o r � _ H o f