For the reaction, $2 \mathrm{H}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow 2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{g})}, \Delta \mathrm{H}^{\circ}=-573.2 \mathrm{~kJ}$ What is heat of decomposition of water per mol?

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Aicharya · Accepted Answer

The given reaction is: $2 \mathrm{H}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow 2 \mathrm{H}_2 \mathrm{O}_{(l)} ; \Delta_{\mathrm{f}} \mathrm{H}^{\circ}=-573.2 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Reversing the above reaction, $2 \mathrm{H}_2 \mathrm{O}_{(l)} \longrightarrow 2 \mathrm{H}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})} \Delta_{\mathrm{d}} \mathrm{H}^{\circ}=573.2 \mathrm{~kJ} \mathrm{~mol}^{-1}$ $\therefore \quad$ For decomposition of 1 mole of water, $\mathrm{H}_2 \mathrm{O}_{(l)} \longrightarrow \mathrm{H}_{2(\mathrm{~g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})} ; \Delta_{\mathrm{d}} \mathrm{H}^{\mathrm{o}}=286.6 \mathrm{~kJ} \mathrm{~mol}^{-1}$

For the reaction, $2 \mathrm{H}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow 2 \mathrm{H}_2…

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