For the reaction,$3 I^{-} + S_2 O_8^{2-} \rightarrow I_3^{-} + 2 SO_4^{2-}$,at a particular time $t$,$\frac{d[SO_4^{2-}]}{dt}$ is $2.2 \times 10^{-2} \ mol \ dm^{-3} \ s^{-1}$. What is the value of $-\frac{d[I^{-}]}{dt}$?

$NO_2$ 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 reaction that occurs in a breath analyser,a device used to determine the alcohol level in a person's blood stream is $2 K_{2}Cr_{2}O_{7} + 8 H_{2}SO_{4} + 3 C_{2}H_{6}O$ $\rightarrow 2 Cr_{2}(SO_{4})_{3} + 3 C_{2}H_{4}O_{2} + 2 K_{2}SO_{4} + 11 H_{2}O$. If the rate of appearance of $Cr_{2}(SO_{4})_{3}$ is $2.67 \ mol \ min^{-1}$ at a particular time,the rate of disappearance of $C_{2}H_{6}O$ at the same time is ...... $mol \ min^{-1}$ (Nearest integer).

Assertion : Ionic reactions are not instantaneous.
Reason : Oppositely charged ions exert strong forces.

If the first order reaction involves gaseous reactants and gaseous products,the units of its rate are:

For the reaction,$2 \ NO_{(g)} + O_{2_{(g)}} \rightarrow 2 \ NO_{2_{(g)}}$. If $\frac{d[NO_2]}{dt} = 0.052 \ mol \ dm^{-3} \ s^{-1}$,calculate the rate of consumption of $NO_{(g)}$.