Hydrazine, $\text{N}_2\text{H}_4$, is employed as a rocket fuel since it reacts with oxygen according to the equation shown, giving gases that are considered environmentally friendly. $\text{N}_2\text{H}_4(\ell) + \text{O}_2(\text{g}) \rightarrow \text{N}_2(\text{g}) + 2\text{H}_2\text{O}(\text{g}) \quad \Delta H = -534\,\text{kJ mol}^{-1}$. Although hydrazine is used as a rocket fuel, it does not ignite spontaneously in oxygen. Which statement accounts for the fact that hydrazine does not burn spontaneously?
- AHydrazine is a liquid.
- BThe activation energy is too high.
- CThe $\text{N}\equiv\text{N}$ bond is very strong.
- DThe reaction is exothermic.