Question

Nitric oxide was reacted with chlorine to produce nitrosyl chloride according to the following equation: 2NO(g) + Cl2(g) ?? 2NOCl(g) The rate constant for this reaction at 25oC is 4.9 X 10-6 L/(mol.s) while the rate constant at 150C is 1.5 X 10-5 L/(mol.s). Use this data to calculate the energy of activation for this reaction.

2) What is the rate constant at 150oC for the reaction in question 1?

3) Does the reaction between acetone and iodine follow the general rule concerning the relation between a 10- degree increase in temperature and the reaction rate? Explain.

4) What effect does acid haveon the rate of the reaction between acetone and iodine? Hint what is its function?

Answer 1

2NO(g) + Cl2(g) 2NOCl(g)

rate constant for this reaction

T₁ = 298, K₁ = K_25^oC = 4.9 X 10^-6 L/(mol.s)

T₂ = 423, K₂ = K_150⁰C = 1.5 X 10^-5 L/(mol.s)

Now,

= (8.314) [(1.5 X 10^-5)/(4.9 X 10^-6)] x [126054/125]

= 25.66 kJ mol^-1

2. Rate constant at 150oC for the reaction in question 1 is given in the question itself, which is 1.5 X 10^-5 Lmol^-1s^-1.

3. The reaction will follow the general Arrhenius equation

k=Ae^-E_a/RT

^{where E_a is Arrhenius activation activation energy and A is Arrhenius pre-exponential factor.}

^{4. Acid will act as an catalyst, will lower the activation energy and thereby fasten the reaction.}