MCQ
What is the enthalpy change for, $2H_2O_2(l) \to 2H_2O(l) + O_2(g)$ if heat of formation of $H_2O_2 (l)$ and $H_2O (l)$ are $-188$ and $-286\, kJ/mol$ respectively? ............. $\mathrm{kJ/mol}$
- ✓$-196$
- B$+ 948$
- C$+ 196$
- D$-948$
✓
Answer
Correct option: A.
$-196$
a
$2{H_2}{O_2}(l) \to 2{H_2}O(l) + {O_2}(g)\,\Delta H = ?$
$2{H_2}{O_2}(l) \to 2{H_2}O(l) + {O_2}(g)\,\Delta H = ?$
$\Delta H = [2 \times \Delta {H_f}\,of\,{H_2}O(l) + (\Delta {H_f}\,of\,{O_2})$ $ - (2 \times \Delta {H_f}\,of\,{H_2}{O_2}(l))]$
$ = [(2 \times - 286) + (0) - (2 \times - 188)]$
$ = [ - 572 + 376] = - 196\,kJ/mol$
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