Explain the difference between instantaneous rate of a reaction and average rate of a reaction.

The rate of reaction is expressed as
$+\frac{1}{2}\frac{d[C]}{dt} = -\frac{1}{3}\frac{d[D]}{dt} = +\frac{1}{4}\frac{d[A]}{dt} = -\frac{d[B]}{dt}$
The reaction is:

The reaction given below $2 NH_{3(g)} \xrightarrow{Pt} N_{2(g)} + 3 H_{2(g)}$ has a rate of reaction of $2.5 \times 10^{-6} \ mol \ dm^{-3} \ sec^{-1}$. What is the rate of formation of $H_{2(g)}$?

$KClO_3 + 6FeSO_4 + 3H_2SO_4 \rightarrow KCl + 3Fe_2(SO_4)_3 + 3H_2O$. The above reaction was studied at $300 \ K$ by monitoring the concentration of $FeSO_4$,where the initial concentration was $10 \ M$ and after half an hour it became $8.8 \ M$. The rate of production of $Fe_2(SO_4)_3$ is $........ \times 10^{-6} \ mol \ L^{-1} \ s^{-1}$.

For the reaction $A + 2B \to C + D$,if $-\frac{d[A]}{dt} = 5 \times 10^{-4} \ mol \ L^{-1} s^{-1}$,then what is the value of $-\frac{d[B]}{dt}$?

From the concentrations of $C_{4}H_{9}Cl$ (butyl chloride) at different times given below,calculate the average rate of the reaction:
$C_{4}H_{9}Cl + H_{2}O \rightarrow C_{4}H_{9}OH + HCl$
during different intervals of time.

$t/s$	$0$	$50$	$100$	$150$	$200$	$300$	$400$	$700$	$800$
$[C_{4}H_{9}Cl]/mol\ L^{-1}$	$0.100$	$0.0905$	$0.0820$	$0.0741$	$0.0671$	$0.0549$	$0.0439$	$0.0210$	$0.017$