What is the order and molecularity of the following elementary reaction?
$2\text{NO}_{2(g)} \rightarrow 2\text{NO}_{(g)} + \text{O}_{2(g)}$, rate $= k \times [\text{NO}_2]^2$

Which of the following nanomaterials has one dimension $< 100$ nm?

In Haber process of production of ammonia $\text{Al}_2\text{O}_3$ is used as

Which of the following pairs of elements does NOT include transition elements?