In a motor vehicle's catalytic converter at $550^{\circ}\text{C}$, nitrogen dioxide reacts with unburnt hydrocarbon fragments such as $\text{CH}_3\bullet$. $4\text{CH}_3\bullet + 7\text{NO}_2 \rightarrow 3\frac{1}{2}\text{N}_2 + 4\text{CO}_2 + 6\text{H}_2\text{O}$ The table below shows different types of energy change for this reaction together with possible explanations for each one. Which row states the energy change for this reaction and the explanation for it?
- Aendothermic; chemical energy is converted to heat energy
- Bendothermic; the $\text{N}\equiv\text{N}$ bond energy is very high
- Cexothermic; $\text{CO}_2$ and $\text{H}_2\text{O}$ have large negative $\Delta H_f^{\circ}$ values
- Dexothermic; double bonds are broken in $\text{NO}_2$