Decomposition of NOCl

Question

The decomposition of NOCl follows the reaction

2NOCl →2NO + Cl2

It is a second- order reaction with k= 6.7 ×10−4 Lmol s at 400 K.

a.) What is the half- life of this reaction if the initial concentration of NOCl is 0.20 mol/L

HINT: t1/2=1k[NOCl]0

b.) What it the rate law for this reaction?

c.) What is the rate of this reaction?

Answer 1

For a 2nd order reaction, the t_1/2 = 1/k[A_o]. Also, note that the units you give for k are incorrect. Units for k in a second order reaction should be M^-1 s^-1 and not Lmol s as given.

a). t_1/2 = 1/6.7x10^-4 M^-1 s^-1 * 0.20 M

t_1/2 = 7.8x10⁴ s

b). rate = k[NOCl]²

c). rate = 6.7x10^-4 M^-1 s^-1 * (0.20 M)²

rate = 2.7x10^-5 M^-1 s^-1