On Easter Sunday, April 3, 1983 , nitric acid spilled from a tank car near
downtown Denver, Colorado. The spill was neutralized with sodium carbonate:
\(2 \mathrm{HNO}_{3}(a q)+\mathrm{Na}_{2} \mathrm{CO}_{3}(s) \longrightarrow 2
\mathrm{NaNO}_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{CO}_{2}(g)\)
a. Calculate \(\Delta H^{\circ}\) for this reaction. Approximately \(2.0 \times
10^{4}\) gal nitric acid was spilled. Assume that the acid was an aqueous
solution containing \(70.0 \% \mathrm{HNO}_{3}\) by mass with a density of \(1.42
\mathrm{~g} / \mathrm{cm}^{3}\). What mass of sodium carbonate was required for
complete neutralization of the spill, and what quantity of heat was evolved?
\(\left(\Delta H_{\mathrm{f}}^{\circ}\right.\) for \(\mathrm{NaNO}_{3}(a q)=-467
\mathrm{~kJ} / \mathrm{mol}\) )
b. According to The Denver Post for April 4, 1983 , authorities feared that
dangerous air pollution might occur during the neutralization. Considering the
magnitude of \(\Delta H^{\circ}\), what was their major concern?