question_answer 59)

  Enthalpy is an extensive property. In general, if enthalpy of an overall reaction \[A\to B\] along one route is \[{{\Delta }_{r}}H\] and\[{{\Delta }_{r}}{{H}_{1}},{{\Delta }_{r}}{{H}_{2}},{{\Delta }_{r}}{{H}_{3}}...........\]represent enthalpies of intermediate reactions leading to product B. What will be the relation between\[{{\Delta }_{r}}H\]for overall reaction and\[{{\Delta }_{r}}{{H}_{1}},{{\Delta }_{r}}{{H}_{2}}......\]etc. intermediate reactions?

Answer:

  Heat of reaction is state function : \[\therefore \]\[{{\Delta }_{r}}H={{\Delta }_{r}}{{H}_{1}}+{{\Delta }_{r}}{{H}_{2}}+{{\Delta }_{r}}{{H}_{3}}+.....\]