Which of the following rate laws has an overall order of $0.5$ for a reaction involving substances $x$,$y$,and $z$?

The reaction rate between two substances $A$ and $B$ is expressed as: $\text{rate} = k[A]^n[B]^m$. If the concentration of $A$ is doubled and the concentration of $B$ is halved,the ratio of the new rate to the initial rate will be:

Which one of the following statements is wrong?

For the reaction $2NOBr(g) \rightarrow 2NO(g) + Br_2(g)$, the rate law is $r = k[NOBr]^2$. If the rate constant $k = 1.62 \text{ M}^{-1} \text{ s}^{-1}$ and the concentration of $NOBr$ is $5 \times 10^{-3} \text{ M}$, what is the rate of the reaction?

What is the order of a reaction which has a rate expression $\text{rate} = K[A]^{3/2}[B]^{-1}$?

The decomposition of dimethyl ether leads to the formation of $CH_4$,$H_2$ and $CO$ and the reaction rate is given by
Rate $= k [CH_3OCH_3]^{3/2}$
The rate of reaction is followed by increase in pressure in a closed vessel,so the rate can also be expressed in terms of the partial pressure of dimethyl ether,i.e.
Rate $= k (p_{CH_3OCH_3})^{3/2}$
If the pressure is measured in $bar$ and time in $minutes$,then what are the units of rate and rate constants?