MCQ
If $\Delta H_f^o$ for ${H_2}{O_2}$ and ${H_2}O$ are $ - 188\,kJ/mole$ and $ - 286\,kJ/mole$. What will be the enthalpy change of the reaction $2{H_2}{O_2}(l) \to 2{H_2}O(l) + {O_2}(g)$

......$kJ/mole$

  • $ - 196$
  • B
    $146$
  • C
    $ - 494$
  • D
    $ - 98$

Answer

Correct option: A.
$ - 196$
(a)${H_2} + {O_2} \to {H_2}{O_2}$ $\Delta H_f^o = - 188\,kJ/mole$….$(i)$
${H_2} + \frac{1}{2}{O_2} \to {H_2}O$ $\Delta H_f^o = - 286\,kJ/mole$….$(ii)$
eq. $(i)$ $-$ eq. $(ii)$ $\times 2$ gives the required result.

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