Consider the following reaction,the rate expression of which is given below:
$A + B \rightarrow C$
$\text{rate} = k[A]^{1/2}[B]^{1/2}$
The reaction is initiated by taking $1 \ M$ concentration of $A$ and $B$ each. If the rate constant $(k)$ is $4.6 \times 10^{-2} \ s^{-1}$,then the time taken for $A$ to become $0.1 \ M$ is . . . . . . . . . . $sec$. (nearest integer)

Given below are two statements:
Statement $I$: The graph of $t_{1/2}$ versus initial concentration $[R]_0$ for a first-order reaction is a horizontal line.
Statement $II$: The graph of $\log \frac{[R]_0}{[R]}$ versus time $t$ for a first-order reaction is a straight line passing through the origin with a slope equal to $\frac{k}{2.303}$.
In the light of the above statements,choose the correct answer from the options given below:

For a first-order reaction, $20 \text{ mmol}$ of reactant is reduced to $10 \text{ mmol}$ in $1.151 \text{ min}$. Find the rate constant $k$. (in $\text{ min}^{-1}$)

For a first order reaction,the ratio between the time taken to complete $\frac{3}{4}$ th of the reaction and time taken to complete half of the reaction is

Hydrolysis of methyl acetate in aqueous solution has been studied by titrating the liberated acetic acid against sodium hydroxide. The concentration of the ester at different times is given below:

Time $(t)$ $\text{min}$	$0$	$30$	$60$	$90$
Conc. of ester $(C)$ $\text{mol L}^{-1}$	$0.850$	$0.800$	$0.754$	$0.710$

Show that it follows a pseudo first-order reaction as the concentration of $H_2O$ remains nearly constant $(54.2 \text{ mol L}^{-1})$ during the course of the reaction. What is the value of $k'$ in this reaction?

For a first-order reaction involving gaseous reactants and gaseous products,what will be the unit of its rate constant?