For a fourth-order reaction,what is the unit of $K$?

The rate of the reaction: $2N_2O_5 \rightarrow 4NO_2 + O_2$ can be written in three ways.
$-\frac{d[N_2O_5]}{dt} = k[N_2O_5]$
$\frac{d[NO_2]}{dt} = k'[N_2O_5]$ ; $\frac{d[O_2]}{dt} = k''[N_2O_5]$
The relationship between $k$ and $k'$ and between $k$ and $k''$ are:

Which of the following statements is incorrect?

For the reaction $A + B \rightarrow$ products,it is observed that
$(i)$ on doubling the initial concentration of $A$ only,the rate of reaction is also doubled and
$(ii)$ on doubling the initial concentration of both $A$ and $B$,there is a change by a factor of $8$ in the rate of the reaction.
The rate of this reaction is given by

The rate law for the reaction $2 NO_{(g)} + O_{2(g)} \longrightarrow 2 NO_{2(g)}$ is $\text{rate} = k[NO]^2[O_2]$. Which of the following statements is correct?

Which of the following statements is true regarding the order of a reaction?