Question

Consider the following proposed mechanisms for Reaction (1): Mechanism A (one step): H2O2 + 2I- +...

Consider the following proposed mechanisms for Reaction (1): Mechanism A (one step): H2O2 + 2I- + 2H3O+ à I2 + 4H2O Reaction (1) Mechanism B (three steps) H2O2 + I- à OH- + HOI (slow) H3O+ + OH- ßà 2H2O (fast) HOI + H3O+ + I- à I2 + H2O (fast) a) Show that when you sum the three elementary steps, the net result of Mechanism B is Reaction (1): b) What would be the expected rate law for mechanism B, assuming that the rate of Reaction (1) is limited by the slow step 1?

Science   Chemistry   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

Mechanism A:

H2O2 + 2 I- + 2 H3O+ ---------> I2 + 4 H2O (Reaction 1)

Mechanism B:

H2O2 + I- --------> OH- + HOI (slow) ……(1)

H3O+ + OH- --------> 2 H2O (fast) ……(2)

HOI + H3O+ + I- --------> I2 + 2H2O (fast) …..(3)

1) Add equations (1)-(3) to get

H2O2 + I- + H3O+ + OH- + HOI + H3O+ + I- ---------> OH- + HOI + 2 H2O + I2 + 2 H2O

Cancel out the common terms to obtain

H2O2 + 2 I- + 2 H3O+ --------> I2 + 4 H2O

This is the same as reaction 1 above.

2) The slowest step of mechanism B determines the rate law for the reaction 1 in mechanism A. The rate law for mechanism B is determined by the slowest step of the reaction, i.e, (1). The rate law for step (1) of mechanism B is given as

Rate = k*[H2O2][I-]

where k = second order rate constant.

We must assume that all the steps (1)-(3) are elementary steps.

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
The following mechanism has been suggested for the reaction: H2O2+2H+2I--->I2+H2O H2O2+I--->HOI+OH (SLOW) OH+H--->H2O (FAST) HOI+H+I--->I2+H2O (FAST)...
The following mechanism has been suggested for the reaction: H2O2+2H+2I--->I2+H2O H2O2+I--->HOI+OH (SLOW) OH+H--->H2O (FAST) HOI+H+I--->I2+H2O (FAST) Identify the molecularity of the rate determining step. please explain why.
The mechanism of a reaction is shown below.             a) What is the overall reaction? b)...
The mechanism of a reaction is shown below.             a) What is the overall reaction? b) Which compounds are intermediates? c) Predict the rate law based on this mechanism. d) What is the overall order of the reaction?             HOOH + I¯      HOI + OH¯        (slow)             HOI + I¯    I2   +   OH¯                 (fast)             2OH¯   +   2H3O+ 4 H2O             (fast)
The mechanism for the reaction 2 H2O2(aq) à 2 H2O(l) + O2(g) in the presence of...
The mechanism for the reaction 2 H2O2(aq) à 2 H2O(l) + O2(g) in the presence of I–(aq) is proposed to be: Step 1: H2O2(aq) + I–(aq) à H2O(l) + OI–(aq)                                   (slow) Step 2: H2O2(aq) + OI–(aq) à H2O(l) + O2(g) + I–(aq)                       (fast) What is the rate law for the overall reaction?             a. Rate = k[H2O2]2             b. Rate = k[H2O2][I–]             c. Rate = k[H2O2]2[I–]/[H2O]             d. Rate = k[H2O2][OI–]             e. Rate = k[H2O2]
The iodide-catalyzed decomposition of hydrogen peroxide is thought to proceed by a four-step mechanism: H2O2(aq) +...
The iodide-catalyzed decomposition of hydrogen peroxide is thought to proceed by a four-step mechanism: H2O2(aq) + I-(aq) --> HOI(aq) + OH-(aq) (slow) HOI(aq) + OH-(aq) --> H2O(l) + OI-(aq) OI-(aq) + H2O2(aq) --> HOOI(aq) + OH-(aq) HOOI(aq) + OH-(aq) --> H2O(l) + O2(g) + I-(aq) (a) If the first step of this mechanism is rate-determining (slow), choose the correct rate law for the overall process. oRate = k [H2O2]2 oRate = k [I-] [H2O2] oRate = k [H2O2] [H2O2] oRate...
The reaction 2 H2O2 --> 2 H2O + O2 follows the mechanism: Step 1: H2O2 (aq)...
The reaction 2 H2O2 --> 2 H2O + O2 follows the mechanism: Step 1: H2O2 (aq) + I-(aq) --> H2O(l) + IO-(aq) SLOW    Step 2: IO-(aq) + H2O2(aq) --> H2O(l) + O2(g) + I-(aq) FAST What is the molecularity overall? A. termolecular B. bimolecular C. cannot be determined D. unimolecular
The following three step mechanism has been proposed for this reaction: Step 1: A + B...
The following three step mechanism has been proposed for this reaction: Step 1: A + B <--> G fast Step 2: A + G --> E + D slow Step 3: E + 2C --> 2D + F fast Determine the rate law predicted by the mechanism. Identify any intermediates shown. The experiemental rate law was determined to be Rate = [A]2[B]. Is this mechanism valid?
Determine the rate law that is consistent with the following mechanism: Step 1: OCl− + H2O...
Determine the rate law that is consistent with the following mechanism: Step 1: OCl− + H2O ⇄ HOCl + OH− (fast) Step 2: I− + HOCl  HOI + Cl− (slow) A) Rate = k[OCl−][H2O] B) Rate = k[I−][HOCl] C) Rate = k[OCl−][H2O][I−] D) Rate = k[OCl−][H2O]/[I−] E) Rate = k[OCl−][H2O]/[OH−] F) Rate = k[OCl−][H2O][I−]/[OH−]
Consider the following proposed two-­‐step mechanism for the reaction: 2A + B à C + D....
Consider the following proposed two-­‐step mechanism for the reaction: 2A + B à C + D. Step 1: A + B ⇄ E Step 2: E + A → C + D a. Is this a reasonable mechanism? Why or why not? b. What are the intermediates in the reaction mechanism? c. Write a rate law for each step. d. Write an overall rate law if the first step is very slow compared to the second step. e. Write an...
Nitramide, NO2NH2, decomposes slowely in aqueous slution according to the following reaction: NO2NH2 (aq) ---> N2O...
Nitramide, NO2NH2, decomposes slowely in aqueous slution according to the following reaction: NO2NH2 (aq) ---> N2O (g) + H2O the reaction follows the rate law: Rate= k(NO2NH2)/(H3O+) *Omit H2O from the rate law that you determine from the Mechanisms* (a) Which of the following mechanisms is the most appropriate for the interpretation of this rate law? Justify your answer. Mechamism 1 NO2NH2 ---> N2O + H2O  rate constant = k1 Mechanism 2 NO2NH2 + H3O+ <---> NO2NH3+ + H2O Fast rate...
A proposed mechanism for a reaction is as follows: Step 1 (fast): A + B <=>...
A proposed mechanism for a reaction is as follows: Step 1 (fast): A + B <=> C Step 2 (slow): C --> D + E Determine the rate law predicted by this mechanism A. Rate = k'[C] B. Rate = k'[A] C. Rate = k'[A][B] D. Rate = k'[B][D]
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT