Question

The bond energy of an O-H bond is 109 kcal mol-!. When a mole of water is formed
(a) 218 kcal is released
(b) 109 kcal is released
(C) 218 kcal is absorbed
(d) 109 kcal is absorbed

Answer 1

Answer:

B

Explanation:

Solution :

Bond energy of O-H bond =109kcal/mol means that whn 1 mole of O-H bonds are formed,109 kcal energy is released ( because dissociation of bond absorbs energy ). Formation of one mole of water is equivalent to formation of2moles of O-H bond ( H-O-H) . Hence,energy released =2×109=218kcal. ( Strictly speaking, we calculate ΔfH∘for the reaction.

H2(g)+12O2(g)→H2O(l).i.e.,(H−O−H)

ΔfH∘=BE(H−H)+12BE(O=O)−2BE(O−H)

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Answer 2

Answer:

218 kcal is absorbed this is the answer of it