Question

3. Look at Figure 16.22 (p.727), the reaction energy diagrams for the two step reactions of a) NO, and F, and b) NO and O2 Write down the mechanisms for both reactions, and these mechanisms based on the corresponding reaction energy diagrams. IMG_0338.jpg v Q Search Depicting a Multistep Mechanism with a Reaction Energy Diagram Figu re 16.22 shows reaction energy diagrams for two reactions, each of which has a two-step mechanism, shown below the diagram. The reaction of NO, and F, (part A) starts with a slow step, and the reaction of NO and O, (part B) starts with a fast step. Both overall reactions are exothermic, so the product is lower in energy than the reactants. Note these key points: • Each step in the mechanism has its own peak with the transition state at the top. • The intermediates (F in part A and NO, in part B) are reactive, unstable species, so they are higher in energy than the reactants or product. • The slow (rate-determining) step (step 1 in A and step 2 in B) has a larger E than the other step. TRANSITION STATES TRANSITION STATES Potential energy NO2F+ F+NO2 Potential energy NO.NO 2NO+ O2 REACTANTS 2NO2 + F2 REACTANTS AHCO 2NO F PRODUCT 2NO2 PRODUCT Reaction progress Reaction progress (1) NO26) +F36) NOFC) + F(g) (slow] (1) NO(g) + O26) NO3(e) [ast] (2) NO2(3)+F8) NOFC) (2) NO3(s) + NO(g) — 2NO() [show] Figure 16.22 Reaction energy diagrams for the two-step reaction of (A) NO, and F, and of (B) NO and Oz.

Answer 1

Answer as for the reaction, 2002 fa 2N02F Activation Enerzig for steps Potential CPIESTI Proposed mechanism can be broken down into two steps fahren 2ND, Reaction. Progress tetet Step - ! -NO, +F4 → NO, f + Step-2 No, t f No of How, from Energy diagram, it com be seen that Step I is stower step of so it is the rate determining step. Howe, we know reaction rate (R) can be written for rate defermining step (rds) as, R = K[No, Iffl k y Rate constant So, one molecule of No, collides with one molecule ofse tovith form Product . CamScanner

b) Same as for part a, by observing Pic diagram we can break the section, - 200 + 2003, into 2 steps as well P.El 2ND Reaction Progress Step-! > NO + O 2 No, ker = falog? - Thollon Step-2 No, &No 200, Since to >> Step 2 is the role So hate of reaction , R = KS No No Now, as tos is a reaction intermediate, it can not be represented in Reaction rase, e, Substituting froz] using equations , we get Roteskeem faros?fo21 ss Rak" [mo? [7 CamScanner

so tua molecules of No Collide with of o to produce {wo molecules sorder of the reaction is } I CamScanner one molecule No. of