\textbf{217-} Nitric acid is industrially produced from the oxidation of ammonia. The amount of heat exchanged per kJ for the production of each mole of nitric acid using the reaction: $\text{NH}_3(\text{g}) + 2\text{O}_2(\text{g}) \rightarrow \text{HNO}_3(\text{aq}) + \text{H}_2\text{O(l)}$, is how much?
1) $4\text{NH}_3(\text{g}) + 5\text{O}_2(\text{g}) \rightarrow 4\text{NO}(\text{g}) + 6\text{H}_2\text{O(l)}\ ,\ \Delta H = a\ \text{kJ}$
2) $3\text{HNO}_3(\text{aq}) + \text{NO}(\text{g}) \rightarrow 3\text{NO}_2(\text{g}) + \text{H}_2\text{O(l)}\ ,\ \Delta H = b\ \text{kJ}$
3) $4\text{NO}_2(\text{g}) \rightarrow \text{O}_2(\text{g}) + 4\text{NO}(\text{g})\ ,\ \Delta H = c\ \text{kJ}$
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(1) $\dfrac{a-b-rc}{2}$ \hfill (2) $\dfrac{a+2b+rc}{2}$ \hfill (3) $\dfrac{-a+b+rc}{4}$ \hfill (4) $\dfrac{a-2b-rc}{4}$
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