K-4 Reaction Mechanisms

Question 1

The following 2 step reaction mechanism has been proposed.

Step 1) NO₂Cl → NO₂ + Cl (slow)

Step 2) NO₂Cl + Cl NO₂ + Cl₂ (fast)

What is the overall reaction for this mechnism?

Answer 1

Overall Reaction: 2NO₂Cl(g) → 2NO₂(g) + Cl₂(g)

Question 2

The following 2 step reaction mechanism has been proposed.

Step 1) NO₂Cl → NO₂ + Cl (slow)

Step 2) NO₂Cl + Cl → NO₂ + Cl₂ (fast)

What reaction intermediates, if any, are present?

Answer 2

Cl is the intermediate

Question 3

The following 2 step reaction mechanism has been proposed.

Step 1) NO₂Cl → NO₂ + Cl (slow)

Step 2) NO₂Cl + Cl → NO₂ + Cl₂ (fast)

What catalysts, if any, are present?

Answer 3

There are no catalysts

Question 4

The following 2 step reaction mechanism has been proposed.

Step 1) NO₂Cl → NO₂ + Cl (slow)

Step 2) NO₂Cl + Cl → NO₂ + Cl₂ (fast)

What is the rate law for the mechanism?

Answer 4

Based on slow step - Rate₁ = k₁[NO₂Cl]

1st order based on molecularity

Question 5

The following 2 step reaction mechanism has been proposed.

Step 1) O₃ + NO₂ → NO₃ + O₂ (slow)

Step 2) NO₃ + NO₂ → N₂O₅ (fast)

What is the overall reaction for this meachnism?

Answer 5

Overall Reaction: O₃(g) + 2NO₂(g) → O₂(g) + N₂O₅(g)

Question 6

The following 2 step reaction mechanism has been proposed.

Step 1) O₃ + NO₂ → NO₃ + O₂ (slow)

Step 2) NO₃ + NO₂ → N₂O₅ (fast)

What reaction intermediates, if any, are present?

Answer 6

NO₃ is a reaction intermediate

Question 7

The following 2 step reaction mechanism has been proposed.

Step 1) O₃ + NO₂ → NO₃ + O₂ (slow)

Step 2) NO₃ + NO₂ → N₂O₅ (fast)

What catalysts, if any, are present?

Answer 7

There are no catalysts.

Question 8

The following 2 step reaction mechanism has been proposed.

Step 1) O₃ + NO₂ → NO₃ + O₂ (slow)

Step 2) NO₃ + NO₂ → N₂O₅ (fast)

What is the rate law for the mechanism?

Answer 8

Based on slow step Rate₁ = k₁[O₃]{NO₂]

2nd order based on molecularity

Question 9

The following 2 step reaction mechanism has been proposed.

Step 1) O₃ + NO → NO₂ + O₂ (slow)

Step 2) NO₂ + O → NO + O₂ (fast)

What is the overall reaction for this mechanism?

Answer 9

Overall Reaction: O₃(g) + O(g) → 2O₂(g)

Question 10

The following 2 step reaction mechanism has been proposed.

Step 1) O₃ + NO → NO₂ + O₂ (slow)

Step 2) NO₂ + O → NO + O₂ (fast)

What reaction intermediates, if any, are present?

Answer 10

NO₂ is a reaction intermediate

Question 11

The following 2 step reaction mechanism has been proposed.

Step 1) O₃ + NO → NO₂ + O₂ (slow)

Step 2) NO₂ + O → NO + O₂ (fast)

What catalysts, if any, are present?

Answer 11

NO is a catalyst

Question 12

The following 2 step reaction mechanism has been proposed.

Step 1) O₃ + NO → NO₂ + O₂ (slow)

Step 2) NO₂ + O → NO + O₂ (fast)

What is the rate law for the mechanism?

Answer 12

Based on the slow step Rate₁ = k₁[O₃][NO]

2nd order based on molecularity

Question 13

The following 2 step reaction mechanism has been proposed.

Step 1: Fe³⁺ (aq) + 2I^- (aq)→ Fe²⁺ (aq) + I₂ (s)
Step 2: S₂O₈^2- (aq) + Fe²⁺ (aq) → 2SO₄^2- (aq) + Fe³⁺ (aq)

What is the overall reaction for this mechanism?

Answer 13

Overall Reaction: 2I^- (aq) + S₂O₈^2- (aq) → I₂ (s) + 2SO₄^2- (aq)

Question 14

The following 2 step reaction mechanism has been proposed.

Step 1: Fe³⁺ (aq) + 2I^- (aq)→ Fe²⁺ (aq) + I₂ (s)
Step 2: S₂O₈^2- (aq) + Fe²⁺ (aq) → 2SO₄^2- (aq) + Fe³⁺ (aq)

What reaction intermediates, if any, are present?

Answer 14

Fe²⁺ is a reaction intermediate

Question 15

The following 2 step reaction mechanism has been proposed.

Step 1: Fe³⁺ (aq) + 2I^- (aq)→ Fe²⁺ (aq) + I₂ (s)
Step 2: S₂O₈^2- (aq) + Fe²⁺ (aq) → 2SO₄^2- (aq) + Fe³⁺ (aq)

What catalysts, if any, are present?

Answer 15

Fe³⁺ is a catalyst

Question 16

The following 2 step reaction mechanism has been proposed.

Step 1: Fe³⁺ (aq) + 2I^- (aq)→ Fe²⁺ (aq) + I₂ (s)
Step 2: S₂O₈^2- (aq) + Fe²⁺ (aq) → 2SO₄^2- (aq) + Fe³⁺ (aq)

What is the rate law for the mechanism?

Answer 16

Based on the slow reaction Rate₁ = k₁[Fe³⁺][I^-]²

3rd order based on molecularity