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.

If the rate of disappearance of $N_2O_5$ in the following reaction is $1.2 \times 10^{-5} \ mol \ L^{-1} \ s^{-1}$,the rate of production of $NO_2$ in $mol \ L^{-1} \ s^{-1}$ is:
$2N_2O_{5(g)} \longrightarrow 4NO_{2(g)} + O_{2(g)}$

For the reaction $N_2 + 3H_2 \rightarrow 2NH_3$,if $\frac{d[NH_3]}{dt} = 2 \times 10^{-4} \ mol \ L^{-1} \ s^{-1}$,then what is the value of $-\frac{d[H_2]}{dt}$?

Explain: What is instantaneous rate? How is it determined?

$NO_2$ required for a reaction is produced by decomposition of $N_2 O_5$ in $CCl_4$ as per the equation $2 \, N_2 O_{5(g)} \rightarrow 4 NO_{2(g)} + O_{2(g)}$. The initial concentration of $N_2 O_5$ is $3 \, mol \, L^{-1}$ and it is $2.75 \, mol \, L^{-1}$ after $30 \, minutes$. The rate of formation of $NO_2$ is $x \times 10^{-3} \, mol \, L^{-1} \, min^{-1}$. The value of $x$ is . . . . . . .

The rate of a chemical reaction can be expressed in terms of: