"Nitric oxide reacts with oxygen to form reddish brown nitrogen dioxide gas". Choose the correct equation for the above reaction

Q. Nitrogen dioxide $\left(N{O}_2\right)$ dissociates into nitric oxide $\left(NO\right)$ and oxygen $\left(O_2\right)$ as follows:
$2N{O}_2\to 2NO+O_2$
If the rate of decrease of concentration of $N{O}_2$ is $6.0\times {10}^{-12}mol{L}^{-1}{s}^{-1}$. What will be the rate of increase of concentration of $O_2$?

Q. Twenty litres of $NO$ gas react with excess oxygen. How many litres of ${NO}_2$ gas are produced if the $NO$ gas reacts completely?

Q. Nitrogen reacts with $O_2$ to form reddish brown fumes of $N{O}_2$.

Q. What is the relation between the equilibrium constants $K$, $K_1$ and $K_2$ for the following reactions?
$N_2+2O_2\leftrightharpoons 2N{O}_2,K$
$N_2+O_2\leftrightharpoons 2NO,K_1$
$2NO+O_2\leftrightharpoons 2N{O}_2,K_2$

Q. Equilibrium constant for the reactions.
$2NO+O_2\rightleftharpoons 2N{O}_2$ is $K_{C_1}$;
$N{O}_2+S{O}_2\rightleftharpoons S{O}_3+NO$ is $K_{C_2}$ and
$2S{O}_3\rightleftharpoons 2s{O}_2+O_2$ is $K_{C_3}$ then correct reaction is: