For the reaction
2H₂(g) + 2NO(g) $$ \to $$ N₂(g) + 2H₂O(g)
the observed rate expression is, rate = K_f[NO]²[H₂]. The rate expression for the reverse reaction is :

NO₂ required for a reaction is produced by the decomposition of N₂O₅ in CCl₄ as per the equation,
2N₂O₅(g) $$ \to $$ 4NO₂(g) + O₂(g).
The initial concentration of N₂O₅ is 3.00 mol L^–1 and it is 2.75 mol L^–1 after 30 minutes. The rate of formation of NO₂ is :

In the following reaction; xA $$ \to $$ yB
$${\log _{10}}\left[ { - {{d\left[ A \right]} \over {dt}}} \right] = {\log _{10}}\left[ {{{d\left[ B \right]} \over {dt}}} \right] + 0.3010$$
'A' and 'B' respectively can be :

For the reaction of H₂ with I₂, the rate constant is 2.5 × 10^–4 dm³ mol^–1s^–1 at 327°C and 1.0 dm³ mol^–1 at 527°C. The activation energy for the reaction, in kJ mole^–1 is : (R = 8.314 JK^–1 mol^–1 )