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:

For a reaction $\frac{1}{2} A \rightarrow 2 B$,the rate of disappearance of $A$ is related to the rate of appearance of $B$ by the expression:

For the decomposition reaction $N_2O_{4(g)} \rightarrow 2NO_{2(g)}$,the initial pressure of $N_2O_4$ decreases from $0.46 \ atm$ to $0.28 \ atm$ in $30 \ minutes$. What is the rate of formation of $NO_2$?

For the reaction $R \rightarrow P$,the concentration of a reactant changes from $0.03 \, M$ to $0.02 \, M$ in $25 \, minutes$. Calculate the average rate of reaction using units of time both in $minutes$ and $seconds$.

In the reaction of formation of sulphur trioxide by contact process $2SO_2 + O_2 \rightleftharpoons 2SO_3$,the rate of reaction was measured as $\frac{d[O_2]}{dt} = -2.5 \times 10^{-4} \ mol \ L^{-1} \ s^{-1}$. The rate of reaction in terms of $[SO_2]$ in $mol \ L^{-1} \ s^{-1}$ will be:

Fill in the blanks:
$(a)$ The rate of reaction ....... as the concentration of reactant decreases.
$(b)$ The rate of reaction ....... as the concentration of product increases.