Complete the sentence using two words. This reaction involves ____________________ ____________________ of the single covalent bond linking a hydrogen atom to a carbon atom in $\text{CH}_3\text{CHO}$.
The hydrogen atom referred to in (a)(i) makes a covalent bond with one of the oxygen atoms in a $\text{NO}_2$ molecule. A $\text{NO}_2$ molecule contains one unpaired electron on the nitrogen atom. In an $\text{HNO}_2$ molecule, all electrons are paired. In the boxes, draw dot-and-cross diagrams for $\text{NO}_2$ and $\text{HNO}_2$. Show only outer-shell electrons.
Use VSEPR theory to estimate the bond angle at the nitrogen atom in an $\text{HNO}_2$ molecule.
The rate equation for the reaction between $\text{CH}_3\text{CHO}$ and $\text{NO}_2$ is given below. $\text{rate} = k[\text{CH}_3\text{CHO}][\text{NO}_2]$. Under some conditions, both $\text{CH}_3\text{CHO}$ and $\text{NO}_2$ have concentrations of $0.200\,\text{mol dm}^{-3}$, and the reaction rate is $1.53 \times 10^{-4}\,\text{mol dm}^{-3}\text{ s}^{-1}$. Calculate the value of the rate constant, $k$, in these conditions. State the units of $k$.
The reaction mixture from (b) is followed over time. Predict whether the graph of $[\text{NO}_2]$ against time has a constant half-life. Explain your answer.
$\text{NO}_2$ also reacts with ozone, $\text{O}_3$. The rate equation is given by $\text{rate} = k_1[\text{NO}_2]$. Under certain conditions, $k_1$ is $0.0848\,\text{s}^{-1}$. The reaction has a constant half-life in these conditions. Calculate the half-life in seconds.
$\text{NO}_2$ is found in car exhaust gases. It can react with carbon monoxide, $\text{CO}$, on the surface of a heterogeneous catalyst in the catalytic converter of a car. Describe how this heterogeneous catalyst works.