Question

A mechanism for a naturally occurring reaction that destroys ozone is:
Step 1: O₃(g) + HO(g) → HO₂(g) + O₂(g)
Step 2: HO₂(g) + O(g) → HO(g) + O₂(g)
Which species is a catalyst and what type of catalysis is occurring?

Select one:

A. HO, heterogeneous

B. HO₂, heterogeneous

C. HO₂, homogeneous

D. HO, homogeneous

The relative initial rates of the reaction A₂ + B₂ → products in vessels (a)-(d) are 1:1:4:4. Unshaded spheres represent A₂ molecules, and shaded spheres represent B₂ molecules present at the beginning of the reaction.

What is the rate law for this reaction?

Select one:

A. Rate = k[A₂]²

B. Rate = k[A₂]²[B₂]²

C. Rate = k[B₂]²

D. Rate = k[A₂][B₂]

The reaction between chlorine and nitric oxide to form nitrosyl chloride is shown below. If the reaction rate doubles when the concentration of Cl₂ is doubled and the rate quadruples when the concentration of NO is doubled, by what factor will the rate increase if both concentrations, NO and Cl₂, are doubled?
Cl₂(g) + 2 NO(g) → 2 NOCl(g)

Select one:

A. 16

B. 8

C. 4

D. 2

Using the method of initial rates for the reaction A → B, if the initial concentration of A is doubled and the rate of reaction quadruples, what is the order of reaction with respect to A?

Select one:

A. second

B. zeroth

C. first

D. fourth

Answer 1

a) HO is catalyst and since the reaction is taking place in gas phase, it is homogeneous ( D is correct)

b)sicne a to d are 1:1 :4:4 ,the rate law is -rA=K[A2] [B2] ( D is correct)

c)since the reaction rate gets doubles when the concentration of Cl2 is doubled, the reaction is first order wtih respect to Cl2 and gets quadrapoled when concentration of NO is doubles, the reaction is 2nd order wtih respect to NO

-rA = rate of reaction = K [ Cl2]1 [NO]2

Cl2 and No both are doubled

-rA= K [2Cl2] [2NO]2= 2*4 [CL2] [NO]2 =8 times initial reaction ( B is correct)

4. -rA= KCAⁿ ,n= order of reaction

CA is doubled, -rA gets qudrapoled

-4ra= K*(2CA)n

4= 2ⁿ

n= 2 ( A is the correct answer)