For the reaction $N_2 + 3H_2 \to 2NH_3$,which of the following represents the correct expression for $d[NH_3]/dt$?

The following results are obtained in the hydrolysis of chlorobutane $(C_4H_9Cl)$:

Time $(s)$	$0$	$100$	$200$	$300$	$400$	$700$	$800$
$[C_4H_9Cl]$ $(mol \, L^{-1})$	$0.100$	$0.082$	$0.067$	$0.055$	$0.044$	$0.021$	$0.017$

Calculate the average rate $r_{av}$ of the reaction during different time intervals.

The instantaneous rate of disappearance of $MnO_4^-$ ion in the following reaction is $4.56 \times 10^{-3} \ M s^{-1}$.
$2MnO_4^- + 10I^{-} + 16H^{+} \to 2Mn^{2+} + 5I_2 + 8H_2O$
The rate of appearance of $I_2$ is $...... \times 10^{-2} \ M s^{-1}$.

For the reaction,$3 I_{(aq)}^{-} + S_2 O_{8_{(aq)}}^{2-} \longrightarrow I_{3_{(aq)}}^{-} + 2 SO_{4_{(aq)}}^{2-}$,the rate of formation of $SO_4^{2-}$ is $0.022 \ mol \ dm^{-3} \ sec^{-1}$. What is the rate of formation of $I_{3_{(aq)}}^{-}$?

In a reaction $A_2B_{3(g)} \to A_{2(g)} + \frac{3}{2}B_{2(g)}$,the pressure increases from $60 \ torr$ to $75 \ torr$ in $2.5 \ min$. The rate of disappearance of $A_2B_3$ is ........ $torr \cdot min^{-1}$.

For the reaction $H_2 + I_2 \rightleftharpoons 2HI$,write the correct relationship between the rates of change of concentration of reactants and products.