The half-life periods of decomposition of $PH_3$ for different initial pressures are given below $:$

Initial Pressure $p$ (torr)	$707$	$79$	$37.5$
Half-life $t_{1/2}$ (min)	$84$	$84$	$84$

Determine the order of the reaction.

What is a pseudo first order reaction? Give an example of a pseudo first order reaction.

The results given in the below table were obtained during kinetic studies of the following reaction:
$2 A + B \longrightarrow C + D$

Experiment	$[A] / mol \ L^{-1}$	$[B] / mol \ L^{-1}$	Initial rate / $mol \ L^{-1} \ min^{-1}$
$I$	$0.1$	$0.1$	$6.00 \times 10^{-3}$
$II$	$0.1$	$0.2$	$2.40 \times 10^{-2}$
$III$	$0.2$	$0.1$	$1.20 \times 10^{-2}$
$IV$	$X$	$0.2$	$7.20 \times 10^{-2}$
$V$	$0.3$	$Y$	$2.88 \times 10^{-1}$

$X$ and $Y$ in the given table are respectively :

For the reaction,$NO_{2(g)} + CO_{(g)} \longrightarrow NO_{(g)} + CO_{2(g)}$,the rate of reaction is proportional to the square of $[NO_2]$ and independent of $[CO]$. What is the rate law equation?

The rate constant for the reaction $2N_2O_5 \to 4NO_2 + O_2$ is $3.0 \times 10^{-5} \, sec^{-1}$. If the rate is $2.40 \times 10^{-5} \, M \, sec^{-1}$,then the concentration of $N_2O_5$ (in $M$) is?

The reaction $CH_{3}COF + H_{2}O \rightleftharpoons CH_{3}COOH + HF$ is studied under two conditions:
Condition $I$: $[H_{2}O]_{0} = 1.00 \ M$,$[CH_{3}COF]_{0} = 0.01 \ M$
Condition $II$: $[H_{2}O]_{0} = 0.02 \ M$,$[CH_{3}COF]_{0} = 0.80 \ M$

Time $(t)$ min (Condition $I$) / $[CH_{3}COF]$ $M$	Time $(t)$ min (Condition $II$) / $[H_{2}O]$ $M$
$0$ / $0.01000$	$0$ / $0.0200$
$10$ / $0.00867$	$10$ / $0.0176$
$20$ / $0.00735$	$20$ / $0.0156$
$40$ / $0.00540$	$40$ / $0.0122$

Determine the overall order of the reaction and calculate the rate constant.