If the relation between half-life time $(t_{1/2})$ and initial concentration $[R]_0$ is given by $t_{1/2} \propto \frac{1}{[R]_0^{n-1}}$,what is the order of the reaction?

For a chemical reaction,$A + 2B \to C + D$,the rate of reaction increases $3$ times when the concentration of $A$ only is increased $9$ times. While when the concentration of $B$ only is increased $2$ times,the rate of reaction also increases $2$ times. The order of this reaction is:

For the following reaction: $NO_{2(g)} + CO_{(g)} \to NO_{(g)} + CO_{2(g)}$,the rate law is: $\text{Rate} = k [NO_2]^2$. If $0.1 \ mol$ of gaseous carbon monoxide is added at constant temperature to the reaction mixture,which of the following statements is true?

The rate constants for first-order and second-order reactions have units of ..... respectively.

What is the order of reaction if the unit of the rate constant is $s^{-1}$?

For a reaction $r = k[A][B]^2$,if the concentration of $A$ is doubled,the rate of reaction: