When the temperature is $550\,^{\circ}\text{C}$, nitrogen dioxide reacts with unburnt hydrocarbon fragments such as $\text{CH}_3$ inside the catalytic converter of a motor vehicle. $\text{4CH}_3 + \text{7NO}_2 \rightarrow 3\tfrac{1}{2}\text{N}_2 + 4\text{CO}_2 + 6\text{H}_2\text{O}$ Which row indicates the energy change for this reaction and a plausible explanation for it?
- Aendothermic; chemical energy is converted to heat energy
- Bendothermic; the N≡N bond energy is very high
- Cexothermic; $\text{CO}_2$ and $\text{H}_2\text{O}$ have negative $\Delta H_f^{\circ}$ values
- Dexothermic; double bonds are broken in $\text{NO}_2$