CHM243H5 Final: Exam Review

1. Which of the following reagent(s) can be used to prepare a mixture of o and p-nitro toluene from toluene

(A) HNO₂ (B) HNO₃ (C) HNO₃/Fe (D) HNO₃/H₂SO₄ (E) NaNO₂

2.

(A) H₂SO₃ (B) SO₃/ Which of the following reagent(s) can be used to convert nitrobenzene to m-nitrobenzenesulfonic acid Fe (C) H₂SO₃/Fe (D) H₂SO₄/Al₂(SO₄)₃ (E) H₂SO₄.SO₃

3. Which of the following reagent(s) can be used to prepare bromobenzene from benzene

(A) NBS (B) Br₂/FeBr₃ (C) H₂SO₄/Br₂ (D) Br₂/AlBr₃ (E) Br₂/Pd

4. Which of the following functional groups are o,p-directing ?

(A) Br, CH₂CH₃, NH₂ (B) Cl, NH₂, COOH (C) I, SO₃H, OH (D) OCH₃, Cl, COCH₃ (E) NO₂, CH₃, OH

5. Which of the following reagent(s) gives the reaction below

(A) CH₃Cl (B) Cl₂/ Fe (C) Cl₂/ AlCl₃ (D) Cl₂/ FeCl₃ (E) Cl₂/ HCl

6. Friedal-Craft acylation reagent(s)

(A) CH₃Cl/AlCl₃ (B) Cl₂/CH₃COCl (C) CH₃COCl/AlCl₃ (D) CH₃COCl/FeCl₃ (E) CH₃Cl/FeCl₃

7. Which of the following functional groups are m-directing ?

(A) NO₂, CH₃, OH (B) Br, NH₂, COOH (C) I, SO₃H, OH (D) OCH₃, Cl, COCH₃ (E) COCH_3, SO₃H, CHO

8. Which of the following compound can be used in the Diels-Alder reaction

(A) 2-methyl, 2,4-hexadiene (B) 2,5-hexadiene (C) 1-methyl,cyclohexa-1,4-diene (D) cyclohexa-1,4-diene

(E) 2-methyl, 1,5-hexadiene

9. Which statement about benzene is incorrect?

(A) The C�C p - bonding is delocalized (B) The C₆ ring is planar (C) The average C - C bond distance is the same as C-C double bonds (D) Each C atom is sp² hybridized ( E ) There are 12 s (sigma) bonds in benzene

10. Which of the following is NOT aromatic

(A) Cyclopropenyl cation (C₃H₃⁺) (B) Benzene (C₆H₆) (C) [16]-Annulene (C₁₆H₁₆)

(D) Cycloheptatrienyl cation (C₇H₇⁺) (E) [18]-Annulene (C₁₈H₁₈)

11. Conjugate addition of one equivalent of deuterium bromide (DBr) to 1,3-butadiene gives

(A) 3-bromo, 4-deutero, 1-butene (B) 3-bromo, 4-deutero, 2-butene (C) 4-bromo, 3-deutero, 1-butene (D) 1-bromo, 4-deutero, 2-butene (E) 1-bromo, 4-deutero, 1-butene

12. Which of the following is a conjugated diene

(A) cyclopentadiene (B) 2-methylcyclohexanone (C) 1-methyl,cyclohexa-1,4-diene (D) cyclohexa-1,4-diene

(E) cycloocta-1,5-diene

13. The aromatic compound is

14. Which of the following reaction involves a benzyne mechanism ?

(A) Ph-CH₃ ? Ph-COOH (B) Ph-CH₃ ? Ph-CHO (C) Ph-OH ? Ph-Cl (D) Ph-Cl ? Ph-OH

(E) none of these

15. Which of the following reagent(s) can be used to prepare a mixture of o and p-nitro toluene from

toluene

(A) HNO₂ (B) HNO₃ (C) HNO₃/Fe (D) HNO₃/H₂SO₄ (E) NaNO₂

16. Friedal-Craft alkyation reagent(s)

(A) C₂H₅Cl/AlCl₃ (B) Cl₂/CH₃COCl (C) CH₃COCl/AlCl₃ (D) CH₃COCl/FeCl₃ (E) CH₃Cl/FeCl₃

17. Which of the following functional groups are o,p-directing ?

(A) NO₂, SO₃H, CHO (B) Br, NH₂, COOH (C) I, OH, CH₃ (D) OCH₃, Cl, COCH₃ (E) COCH_3, SO₃H, Br

18. Major product in the reaction of benzene with 1-bromopropane, in the presence of AlBr₃ catalyst

(A) bromobenzene (B) n-propylbenzene (C) iso-propylbenzene (D) o-bromo-n-propylbenzene

(E) p-bromo-n-propylbenzene

19. Which of the following is the electrophile in the nitration reaction

(A) ⁺HNO₂ (B) NO₂⁺ (C) N₂+ (D) HNO₃/H₂SO₄ (E) NO₃⁺

20. Which of the following is the electrophile in the sulfonation reaction

(A) ⁺HSO₂ (B) SO₂⁺ (C) SO₃⁺ (D) SO₃/H₂SO₄ (E) HSO₃⁺

21. Which of the following is the electrophile in the Friedel-Craft acylation reaction

(A) RCO₂⁺ (B) RCO⁺ (C) CO₂⁺ (D) RX/H₂SO₄ (E) RCO₃⁺

22. The benzyne intermediate has �� p bonds

(A) 1 (B) 2 (C) 3 (D) 4 (E) 5

23. The reagent used for Allylic/benzylic bromination is:

(A) NBS (B) Br₂/ Fe (C) Br₂/ AlBr₃ (D) Br₂/ FeBr₃ (E) Br₂/ HBr

24. Which of the following is an oxidation reagent

(A) H₂SO₄ (B) KMnO₄ (C) KMnO₂ (D) NaBH₄ (E) AlCl₃

25. The formula of fuming sulfuric acid

(A) H₂SO_4.SO₃ (B) H₂SO_4.SO₂ (C) H₂SO_4.HSO₂ (D) H₂SO_4.HSO₃ (E) H₂SO_4.SO

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26. How do you prepare the following compounds, starting from benzene ?

(a). aniline (b). Iodo benzene (c). benzoic acid (d). benzylbromide (e). m-methyl benzoic acid

(f). p-nitrobenzoic acid (g) m-nitrobenzoic acid (h). p-chlorobenzenesulfonic acid (i). m-chlorobenzenesulfonic

acid (j) 3-isopropyl benzoic acid (k). 4-isopropyl toluene

27. Draw the product(s) from the following reactions showing the mechanisms

(a) 1,3-butadiene with acrylonitrile

(b) 1,3-butadiene with one eqv. HBr

(c) 1,3-cyclohexadiene with acrylonitrile

(d) 1,3-cyclohexadiene with one eqv. HBr

(e) 1,3-cyclohexadiene with two eqv. HBr

(f) cyclopentadiene with two eqv. HBr

28. How do you prepare the following compounds, starting from toluene ?

(a). benzoic acid (b). benzyl alcohol (c). m-bromobenzoic acid (d). m-methylbenzoic acid (e). m-nitro

benzoic acid (f). p-nitrobenzoic acid

29. What is/are the product(s) expected when ethylbenzene is reacted with

(a). NBS

(b). Br₂/FeBr₃

(c). KMnO₄, then H⁺

(d). fuming H₂SO₄

(e). NBS, then aq. NaOH

(f) iso-butylbromide/AlBr₃

± Cell Potential and Equilibrium
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Constants | Periodic Table
The equilibrium constant, K, for a redox reaction is related to the standard potential, E?, by the equation
lnK=nFE?RT
where n is the number of moles of electrons transferred, F (the Faraday constant) is equal to 96,500 C/(mol e?) , R (the gas constant) is equal to 8.314 J/(mol?K) , and T is the Kelvin temperature.
Standard reduction potentials
Reduction half-reaction E? (V)
Ag+(aq)+e??Ag(s) 0.80
Cu2+(aq)+2e??Cu(s) 0.34
Sn4+(aq)+4e??Sn(s) 0.15
2H+(aq)+2e??H2(g) 0
Ni2+(aq)+2e??Ni(s) ?0.26
Fe2+(aq)+2e??Fe(s) ?0.45
Zn2+(aq)+2e??Zn(s) ?0.76
Al3+(aq)+3e??Al(s) ?1.66
Mg2+(aq)+2e??Mg(s) ?2.37

Part A Part complete
Use the table of standard reduction potentials given above to calculate the equilibrium constant at standard temperature (25 ?C) for the following reaction:
Fe(s)+Ni2+(aq)?Fe2+(aq)+Ni(s)
Express your answer numerically.
View Available Hint(s)
K = 2.68×10^6 Correct
When E?>0 and K>1 the reaction favors the products.

Part B
Calculate the standard cell potential (E?) for the reaction
X(s)+Y+(aq)?X+(aq)+Y(s)
if K = 7.87×10?3.

Express your answer to three significant figures and include the appropriate units.

E? = ?

Consider a dilute solution of glucose in water at 25 oC. The solution was in a horizontal tube of length 10 cm, at was prepared such that there was a linear gradation of glucose concentration from cglucose(0, 0) = 0.1M at x = 0 cm to cglucose(0, 10cm) = 0.05M at x = 10 cm. (A) What is the force (and direction) acting at the center of the tube (x = 5 cm)? Derive a formula for cglucose(0, x) for x ∈ [0, 10]cm. (B) We wish to solve the time time dependence of cglucose(t, x) for all times t > 0. The next steps of this question will lead you through how to solve such a problem. Consider Fick’s second law of diffusion in one dimension, ∂c ∂t = D ∂ 2 c ∂x2 (2) Show that a function of the form c(t, x) = exp(λt) × (Aeikx + Be−ikx) satisfies Eq. (2) when λ is related to k and D. Determine λ for such a solution. (C) For the problem like that considered in (A) for particles confined to a a region of length L where x ∈ (0, L) (in (A), L = 10 cm, for example) The flux at the end of the containers is equal to zero (no particles leave or enter the container). Mathematically, this imposes a boundary condition that J(x → 0−) = J(x → L+) = 0 (x → 0− means you approach x = 0 from the left and x → L+ means you approach x = L from the right). Show that these boundary conditions imply that A = B and k ≡ kn = nπ L for n = 0, 1, 2, ...∞. That is, show that solutions look like 2Aeλnt cos nπx L (where we now relate λn to kn). (D) Spatially normalize the solutions. Let’s denote the solutions to Eq. (2) with the above boundary conditions as cn(t, x) = A˜ ne λnt cos nπx d for n = 0, 1, 2, ...∞. We wish to verify that at t = 0, these solutions are orthonormal. What the means is we want to show: Z L 0 dxcn(0, x)cm(0, x) = 0 (3) for n 6= m and Z L 0 dxc0(0, x)c0(0, x) = L(A˜ 0) 2 = 1 Z L 0 dxcn6=0(0, x)cn6=0(0, x) = L 2 (A˜ n) 2 = 1 (4) 3 (Hint: it may be easier to verify the above integrals using the relationships that cos(θ) = e iθ+e−iθ 2 and sin(θ) = e iθ−e−iθ 2i ). From the above orthonormality conditions, determine what An for n = 0, 1, 2, ...∞. (E) Superposition principle. Verify that c(t, x) = P∞ n=0 bncn(t, x) satisfies Eq. (2) and also the boundary condition that ∂c(t,x) ∂x x→0− = ∂c(t,x) ∂x x→L+ = 0. The coefficients, bn are simple numbers telling you how much of cn(t, x) is part of your solution for c(t, x). (F) Imposing the initial condition at t = 0. Suppose that at t = 0, c(0, x) = F +Gx for x ∈ (0, L) and c(0, x) = 0 for x ≤ 0 and x ≥ L, i.e., there is a linear gradation to the concentration within the sample region. By the superposition principle, we can write c(t, x) as c(t, x) = X n=0 bncn(t, x) (5) At t = 0 we must have: c(0, x) = F + Gx = X n=0 bncn(0, x) (6) Using orthonormality conditions you derived above, show that bn = Z L 0 dxcn(0, x)(F + Gx) (7) Explicitly determine formulas for b0 and bn6=0. Using these expressions, finally write out your solution to c(t, x). (G) Finally, let’s go back to (A) and determine how the glucose concentration changes with time. The diffusion coefficient for glucose in water is D = 5.7 × 10−10 m2 s . Numerically calculate cglucose(t, x) for x ∈ (0, L) at t = 0.5 s, t = 1s, t = 10s, and t = 1000 s. You will need to approximate your formulas for c(t, x) by taking only a finite number of terms.