What are the shapes of ethyne and methane?

In $Fe(CO)_5$,the $Fe-C$ bond possesses

The number of electrons in the valence shell of the central atom of a molecule is $8$. The molecule is

Which of the following statements is not true?

The average kinetic energy of hydrogen molecules at $300 K$ is $E.$ At the same temperature,the average kinetic energy of oxygen molecules will be

The rate constant for the reaction,$2 \ N_2O_{5(g)} \longrightarrow 2 \ N_2O_{4(g)} + O_{2(g)}$ is $4.98 \times 10^{-4} \ s^{-1}$. What is the order of reaction?