For the reaction $2A + B \rightarrow \text{Product}$,the half-life remains unchanged when the concentration of $A$ is doubled. When the concentration of $B$ is doubled,the rate of reaction increases by a factor of $2$. What is the unit of the rate constant for this reaction?

What is the order and molecularity of the following elementary reaction? $2NO_2(g) \rightarrow 2NO(g) + O_2(g)$, rate $= k[NO_2]^2$

For a particular reaction,the rate expression is given as $r = k[A][B]^{0.5}$. If the volume of the vessel is reduced to one-fourth of the initial volume,the rate of reaction would

Consider the following single step reaction in gas phase at constant temperature.
$2 \ A_{(g)} + B_{(g)} \rightarrow C_{(g)}$
The initial rate of the reaction is recorded as $r_1$ when the reaction starts with $1.5 \ atm$ pressure of $A$ and $0.7 \ atm$ pressure of $B$. After some time,the rate $r_2$ is recorded when the pressure of $C$ becomes $0.5 \ atm$. The ratio $r_1 : r_2$ is $\qquad$ $\times 10^{-1}$.
(Nearest integer)

By “the overall order of a reaction”,we mean

Half-life of a reaction is found to be inversely proportional to the fifth power of its initial concentration,the order of reaction is