For a large excess of oxygen, O₂, the rate of production of nitrogen dioxide, NO₂, by the gas-phase oxidation of nitric oxide, NO
2 NO(g) + O₂ $\rightarrow$ 2 NO₂(g) is found to be independent of the partial pressure of oxygen present. Under these conditions, the rate of formation of nitrogen dioxide was measured to be 8.34 * 10^-13 s^-1 for a concentration of nitric oxide of 5.38 *10^-6 mol dm^-3. Use the description of the mechanism of the reaction given in section 11.5 to determine the rate constant for the dimerization of nitric oxide
2 NO(g) $\rightarrow$ N₂O₂(g) .

Question

For a large excess of oxygen, O₂, the rate of production of nitrogen dioxide, NO₂, by the gas-phase oxidation of nitric oxide, NO
2 NO(g) + O₂

\rightarrow

2 NO₂(g) is found to be independent of the partial pressure of oxygen present. Under these conditions, the rate of formation of nitrogen dioxide was measured to be 8.34 * 10^-13 s^-1 for a concentration of nitric oxide of 5.38 *10^-6 mol dm^-3. Use the description of the mechanism of the reaction given in section 11.5 to determine the rate constant for the dimerization of nitric oxide
2 NO(g)

\rightarrow

N₂O₂(g) .

Quizplus · Accepted Answer

The rate of formation of nitrogen dioxide is given by:$$Rate = k[NO]^2[O_2]$$Since the rate is independent of the partial pressure of oxygen, the rate constant for the dimerization of nitric oxide is:$$k = \frac{Rate}{[NO]^2} = \frac{8.34 	imes 10^{-13} s^{-1}}{(5.38 	imes 10^{-6} mol dm^{-3})^2} = 14.4 	imes 10^{-3} dm^6 mol^{-2} s^{-1}$$

For a Large Excess of Oxygen, O2, the Rate of Production

For a Large Excess of Oxygen, O₂, the Rate of Production