Consider the following reactions: (i) H ( a q ) + + OH ( a q ) − → H 2 O ( i ) , Δ H = − X 1 kJ mol − 1 (ii) H 2 ( a q ) + 2 1 O 2 ( a q ) → H 2 O ( I ) Δ H = − X 2 kJ mol − 1 (i

Question

Consider the following reactions: (i) H ( a q ) + ​ + OH ( a q ) − ​ → H 2 ​ O ( i ) ​ , Δ H = − X 1 ​ kJ mol − 1 (ii) H 2 ( a q ) ​ + 2 1 ​ O 2 ( a q ) ​ → H 2 ​ O ( I ) ​ Δ H = − X 2 ​ kJ mol − 1 (iii) CO 2 ( g ) ​ + H 2 ( g ) ​ → CO ( g ) ​ + H 2 ​ O , Δ H = − X 3 ​ kJ mol − 1 (iv) C 2 ​ H 2 ( g ) ​ + 2 5 ​ O 2 ( g ) ​ → 2 CO 2 ( g ) ​ + H 2 ​ O ( i ) , ​ Δ H = + X 4 ​ kJ mol − 1 Enthalpy of formation of H 2 ​ O ( l ) ​ is:NEET 2007

TestHub · Accepted Answer

The given reaction represents the formation of H 2 ​ O , and the X 2 ​ represents the enthalpy of formation of H 2 ​ O . The enthalpy of formation is the heat evolved or absorbed when one mole of substance is formed from its constituent atoms. Related Theory A negative enthalpy change represents an exothermic change where energy is released from the reaction, a positive enthalpy change represents an endothermic reaction where energy is taken in from the surroundings.

Chemistry - Thermochemistry Question with Solution | TestHub

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