Question

Rate of formation of a dimer in the second order dimerisation reaction is 9.1*10^-6 mol l/sec at 0.01 mol/lite monomer concentration.What is the value of rate constant.Give the relationship between reaction constant and Arrhenius equation?

Answer 1

Answer: -

For a second order reaction,

Rate of the reaction = Rate constant x [Reactant]²

We are told rate = 9.1 x 10⁻⁶ mol litre /sec

The Reactant here is the monomer.

[Reactant] = 0.01 mol/ litre

Rate constant = $\frac{9.1 x 10-6}{0.01 2}$

= 9.1 x 10⁻² mol⁻¹ sec⁻¹

The arrhenius equation is

k = A e ^ $\frac{-Ea}{RT}$

where k is rate constant.

R is universal gas constant.

Ea is activation energy.

A is the frequency factor.

T is the temperature.

Answer 2

Given that the dimerization reaction is of second order.

The rate law for second order reaction is,

$Rate = k[A]^{2}$

$k = R/[A]^{2}$

k = Rate constant of the second order dimerization reaction.

[A] = Monomer concentration.

R = rate of the reaction

$R = 9.1*10^{-6}$$mol.l/s$

$[A]^{2} =0.0001$ $mol^{2}/L^{2}$

So the rate constant k,

$k = \frac{Rate}{[A]^{2}}$

$k = \frac{9.1*10^{-6} mol/L/s}{0.0001 mol^{2}/L^{2}}$

$k = 0.091 mol^{-1} L/s$

Therefore, the rate constant of the given reaction is $0.091mol^{-1}L/s$

The relation between rate constant and Arrhenius Equation is,

$k = A*e^{-Ea/RT}$