Consider the following single step reaction in gas phase at constant temperature.

$2 \mathrm{~A}_{(\mathrm{g})}+\mathrm{B}_{(\mathrm{g})} \rightarrow \mathrm{C}_{(\mathrm{g})}$

The initial rate of the reaction is recorded as $r_1$ when the reaction starts with $1.5 \mathrm{~atm}$ pressure of $\mathrm{A}$ and $0.7 \mathrm{~atm}$ pressure of B. After some time, the rate $r_2$ is recorded when the pressure of $C$ becomes $0.5 \mathrm{~atm}$. The ratio $r_1: r_2$ is $\qquad$ $\times 10^{-1}$.

(Nearest integer)

The decomposition of dimethyl ether leads to the formation of $CH _{4}, H _{2}$ and $CO$ and the reaction rate is given by

Rate $=k\left[ CH _{3} OCH _{3}\right]^{3 / 2}$

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 $=k\left(p_{ CH _{3} OCH _{3}}\right)^{3 / 2}$

If the pressure is measured in bar and time in minutes, then what are the units of rate and rate constants?

Why molecularity is applicable only for elementary reactions and order is applicable for elementary as well as complex reactions ?

For a certain reaction the expression for half life is $t \propto \frac{1}{{{a^{n - 1}}}}$ then the order of reaction is

When a reaction is progressing

Define following term / Give definition :

$(1)$ Elementary reaction

$(2)$ Complex reaction