So this is an online hw problem and I\'ve included my answers/guesses. I\'m real
ID: 805784 • Letter: S
Question
So this is an online hw problem and I've included my answers/guesses. I'm really confused about how to get the overall equation, identifying intermediates, and writing rate laws. Consider the following mechanism.
(a) What is the overall equation? (Use the lowest possible coefficients. Include states-of-matter under SATP conditions in your answer.)
chemPad
My guess: ClO-(aq) + I-(aq) ? Cl-(aq) + IO-(aq)
Your answer contains an improperly or incompletely formatted chemical formula. Your answer is missing one or more subscripts or superscripts.
(b) Identify the intermediates, if any. (Separate substances in a list with a ",". Omit states-of-matter in your answer.)
chemPad
My guess: HIO, Cl-
Your answer differs too much from the expected answer to provide useful feedback.
(c) What are the molecularity and the rate law for each step?
unimolecular
bimolecular
trimolecular
chemPad
Help
My Guess: rate = k[HClo][OH-]
Remember that answers are case-sensitive. Parts of the formula in your answer are transposed. Parts of a formula in your answer appear to be transposed.
unimolecular
bimolecular
trimolecular
chemPad
My Guess: rate = k[HIO][Cl-]
Your answer appears to be missing a charge. Your answer contains an incorrect or incomplete chemical formula. Parts of a formula in your answer appear to be transposed. The equation described in your answer is not balanced.
unimolecular
bimolecular
trimolecular
chemPad
My Guess: rate = k[H2O][IO-]
Your answer contains an incorrect or incomplete chemical formula. Parts of a formula in your answer appear to be transposed.
(d) Is the mechanism consistent with the actual rate law: rate = k[ClO-][I -]?
Yes or No
Show My Work
Step (1)(forward
step only)
unimolecular
bimolecular
trimolecular
chemPad
Help
My Guess: rate = k[HClo][OH-]
Remember that answers are case-sensitive. Parts of the formula in your answer are transposed. Parts of a formula in your answer appear to be transposed.
Step (2)unimolecular
bimolecular
trimolecular
chemPad
My Guess: rate = k[HIO][Cl-]
Your answer appears to be missing a charge. Your answer contains an incorrect or incomplete chemical formula. Parts of a formula in your answer appear to be transposed. The equation described in your answer is not balanced.
Step (3)unimolecular
bimolecular
trimolecular
chemPad
My Guess: rate = k[H2O][IO-]
Your answer contains an incorrect or incomplete chemical formula. Parts of a formula in your answer appear to be transposed.
Explanation / Answer
ANSWER :
Step 1: ClO-(aq) + H2O(I) ---> HClO(aq) + OH-(aq) fast
Step 2: I-(aq) + HClO(aq) ---> HIO(aq) + Cl-(aq) slow
Step 3: OH-(aq) + HIO(aq) ---> H2O(l) + IO-(aq) fast
I SUM ALL THREE STEPs AND I OBTAINED
ClO-(aq) + HClO(aq) + I-(aq) + HIO(aq) + OH-(aq) + H2O(aq) --->
---> Cl-(aq) + HClO(aq) + IO-(aq) + HIO(aq) + OH-(aq) + H2O(aq)
SO I MAY RETRIEVE
ANSWER (a) ClO-(aq) + I-(aq) ---> Cl-(aq) + IO-(aq)
ANSWER (b) Intermediates are HIO and HClO
ANSWER (c)
What are the molecularity and the rate law for each step?
STEP 1 (ClO- (aq) + H2O (l) HClO (aq) + OH- (aq) ) OBEYS TO
Reaction Rate = k1 * |ClO-|
AND HAS MOLECULARITY AS TWO.
STEP 2 (I-(aq) + ClO-(aq) ---> HIO(aq) + Cl-(aq)) OBEYS TO
Reaction Rate = k2 * |ClO-| * |I-|
AND HAS MOLECULARITY AS TWO.
STEP 3 (OH-(aq) + HIO(aq) ---> IO-(aq) + H2O(aq)) OBEYS TO
Reaction Rate = k3 * |HIO| * |OH-|
AND HAS MOLECULARITY AS TWO.
ANSWER (d)
"Is this mechanism consistent with the actual rate law,
e.g. rate = k[ClO-][I-]?"
YES, IT IS. WHY?
SLOWEST STEP OBEYS TO
Reaction Rate = k2 * |HClO| * |I-|
BUT YOU HAVE TO REMEMBER THAT "HClO" ISN'T INITIALLY PRESENT.
INDEED, "HClO" COMES FROM "ClO- + H2O", SO I HAVE TO SUPPOSE "|HClO| = K * |ClO-|" (e.g. chemists obmitted |H2O| since Water results solvent).
FINALLY, I GET
Reaction Rate = k2 * K * |ClO-| * |I-|
MOREOVER, I REMARK THAT GIVEN RATE LAW COMES FROM SETTING-UP SLOWEST STEP AND ITS PRECEEDING ONEs.
FURTHERMORE, YOU CAN'T GET RATE LAW FROM GLOBAL EQUATION.
I hope this helps you.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.