General Chemistry: Principles and Modern Applications

Ralph H. Petrucci, F. Geoffrey Herring, Jeffry D. Madura, Carey Bissonnette

Chapter 27

Reactions of Organic Compounds - all with Video Answers

Educators

Chapter Questions

Problem 1

Describe what is meant by each of the following reaction types, and illustrate with an example: (a) nucleophilic substitution reaction; (b) electrophilic substitution reaction; (c) addition reaction; (d) elimination reaction; (e) rearrangement reaction.

Catherine Lemar

Catherine Lemar

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Problem 2

Describe what is meant by each of the following reaction types, and illustrate with an example from the text: (a) dehydration; (b) hydrolysis; (c) solvolysis;
(d) hydration of an alkene.

Catherine Lemar

Catherine Lemar

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Problem 3

Identify the following types of reactions.

Catherine Lemar

Catherine Lemar

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Problem 4

Identify the following types of reactions.

Catherine Lemar

Catherine Lemar

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Problem 5

Write a balanced chemical equation for the reaction that is described and then classify the reaction as a substitution, an elimination, an addition, or a rearrangement reaction:
(a) Ethene and $\mathrm{Br}_{2}$ react in carbon tetrachloride to give 1,2 -dibromoethane.
(b) Iodoethane reacts with KOH(aq) yielding ethene, water, and potassium bromide.
(c) Chloromethane reacts with $\mathrm{NaOH}($ aq) to give methanol and sodium chloride.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 6

Write a balanced chemical equation for the reaction that is described and then classify the reaction as
a substitution, an elimination, an addition, or a rearrangement reaction.
(a) 3,3 -dimethylbut-1-ene reacts in acid solution to yield 2,3-dimethylbut-2-ene.
(b) 1 -iodo-2,2-dimethylpropane reacts with water to produce, 2,2 -dimethylpropan- $1-$ ol, and $\mathrm{HI}(\text { aq })$.
(c) 2 -chloro- 2 -methylpropane reacts with $\mathrm{NaOH}(\mathrm{aq})$ to give 2 -methylprop-1-ene, sodium chloride, and water.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 7

Write equations for the substitution reaction of 1-bromobutane, a typical primary haloalkane, with the following reagents: (a) $\mathrm{NaOH} ;$ (b) $\mathrm{NH}_{3} ;$ (c) $\mathrm{NaCN}$; (d) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{ONa}$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 8

Write equations for the substitution reaction of 1-bromo-3-methylbutane, a primary haloalkane, with the following reagents: (a) $\mathrm{NaN}_{3} ;$ (b) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{ONa}$ (c) $\mathrm{CH}_{3} \mathrm{C}=\mathrm{CNa} ;$ (d) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{SNa} ;$ (e) $\mathrm{CH}_{3}$ COONa.

Vasu Makani

Numerade Educator

Problem 9

Answer the following questions for this $S_{\mathrm{N}}$ 2 reaction:
$$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}+\mathrm{NaOH} \longrightarrow \quad\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{NaBr}$$(a) What is the rate expression for the reaction?
(b) Draw the reaction profile for the reaction. Label all parts. Assume that the products are lower in energy than the reactants.
(c) What is the effect on the rate of the reaction of doubling the concentration of 1-bromobutane?
(d) What is the effect on the rate of the reaction of halving the concentration of sodium hydroxide?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 10

Answer the following questions for this $S_{\mathrm{N}} 1$ reaction:(a) What is the rate expression for the reaction?
(b) Draw the reaction profile for the reaction. Label all parts. Assume that the products are lower in energy than the reactants.
(c) What is the effect on the rate of the reaction of doubling the concentration of 2 -bromo- 2 -methylpentane?
(d) The solvent for the reaction is ethanol. What is the effect on the rate of the reaction of adding more ethanol?

Vasu Makani

Numerade Educator

Problem 11

Answer the following questions for this E2 reaction:
$$\begin{aligned}
\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}+\mathrm{NaOH} & \longrightarrow \\
\mathrm{CH}_{3} \mathrm{CH} &=\mathrm{CH}_{2}+\mathrm{NaBr}+\mathrm{H}_{2} \mathrm{O}
\end{aligned}$$
(a) What is the rate expression for the reaction?
(b) Draw the reaction profile for the reaction. Label all parts. Assume that the products are lower in energy than the reactants.
(c) What is the effect on the rate of the reaction of doubling the concentration of $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br} ?$
(d) What is the effect on the rate of the reaction of halving the concentration of NaOH?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 12

Answer the following questions for this E1 reaction:
$$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{C}\left(\mathrm{CH}_{3}\right)_{2} \mathrm{Br}+\mathrm{CH}_{3} \mathrm{OH} \longrightarrow \quad\mathrm{CH}_{3} \mathrm{CH}=\mathrm{C}\left(\mathrm{CH}_{3}\right)_{2}+\mathrm{Br}^{-}+\mathrm{CH}_{3} \mathrm{OH}_{2}^{+}$$
(a) What is the rate expression for the reaction?
(b) Draw the reaction profile for the reaction. Label all parts. Assume that the products are lower in energy than the reactants.
(c) What is the effect on the rate of the reaction of doubling the concentration of $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{C}\left(\mathrm{CH}_{3}\right)_{2} \mathrm{Br} ?$
(d) What is the effect on the rate of the reaction of doubling the concentration of $\mathrm{CH}_{3} \mathrm{OH}$ ?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 13

Identify the nucleophile, electrophile, and leaving group in each of the following substitution reactions. Predict whether equilibrium favors the reactants or products:
$$\begin{aligned}
&\text { (a) } \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{ONa}+\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{I} \rightleftharpoons\\
&&\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OCH}_{2} \mathrm{CH}_{3}+\mathrm{NaI}
\end{aligned}$$
$$\begin{aligned}
&\text { (b) } \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{3}^{+}+\mathrm{KI} \rightleftharpoons\\
&&\mathrm{NH}_{3}+\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{I}+\mathrm{K}^{+}
\end{aligned}$$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 14

Identify the nucleophile, electrophile, and leaving group in each of the following substitution reactions. Predict whether equilibrium favors the reactants or products: $$\begin{aligned}
&\text { (a) } \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{I}+\mathrm{NaN}_{3} \longrightarrow\\
&&\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{N}_{3}+\mathrm{NaI}
\end{aligned}$$
$$\text { (b) } \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2}+\mathrm{NaBr} \longrightarrow \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Br}+\mathrm{NaNH}_{2}$$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 15

Molecule (a) below reacts faster in the $S_{N} 2$ reaction than does molecule (b). Explain this observation. [Hint: Draw chair structures for the most stable conformations of the two molecules.]

Catherine Lemar

Catherine Lemar

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Problem 16

Molecule (a) below reacts faster in the $S_{\mathrm{N}} 1$ reaction than does molecule (b). Explain this observation. [Hint: Draw chair structures for the two molecules.]

Vasu Makani

Numerade Educator

Problem 17

A sample of $(S)-C H_{3} C H_{2} C H\left(C H_{3}\right) C l$ is hydrolyzed by water, and the resulting solution is optically inactive.
(a) Write the formula of the product. (b) By which nucleophilic substitution reaction mechanism does this reaction occur?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 18

A sample of $(R)-C H_{3} C H_{2} C H\left(C H_{3}\right) C l$ reacts with $\mathrm{CH}_{3} \mathrm{O}^{-}$ in dimethyl sulfoxide, $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SO},$ a convenient solvent for organic reactions. The resulting solution is optically active. (a) Write the formula of the product. (b) By which mechanism does this nucleophilic substitution reaction occur?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 19

A sample of $(S)-C H_{3} C H(C l) C H_{2} C H_{3}$ is dissolved in ethanol, and the resulting solution is optically inactive. (a) Write the formula of the product. (b) By which mechanism does this nucleophilic substitution reaction occur?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 20

A sample of $(R)$ -2-iodobutane, $(R)-C H_{3} C H_{2} C H(I) C H_{3}$ reacts with KCN in aqueous medium, and the resulting solution is optically active. (a) Write the formula of the product. (b) By which mechanism does this nucleophilic substitution reaction occur?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 21

Give the major products obtained in each of the following reactions and indicate which mechanisms are involved:

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 22

Give the major products obtained in each of the following reactions and indicate which mechanisms are involved:

Catherine Lemar

Catherine Lemar

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Problem 23

Predict the major organic product obtained in each of the following reactions. Assume that [O] represents $\mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ in $\mathrm{H}_{2} \mathrm{SO}_{4}:$
(a) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{OH}+\mathrm{HBr} \longrightarrow$
(b) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}+\mathrm{K} \longrightarrow$
(c) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHOH} \stackrel{[\mathrm{O}]}{\longrightarrow}$
(d) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{I} \longrightarrow$

Catherine Lemar

Catherine Lemar

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Problem 24

Predict the products of the following reactions. Assume that $[\mathrm{O}]$ represents $\mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ in $\mathrm{H}_{2} \mathrm{SO}_{4}$ :
(a) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{OH} \stackrel{(\mathrm{O}]}{\longrightarrow}$
(b) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}+\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCOOH} \stackrel{\mathrm{H}^{+}}{\Delta}$
(c) 3 -methylbut- $2-\mathrm{ol}+\mathrm{NaCl} \stackrel{\mathrm{H}_{2} \mathrm{SO}_{4}}{\longrightarrow}$
(d) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH} \frac{\mathrm{H}_{2} \mathrm{SO}_{4}}{\Delta}$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 25

Explain how you could carry out the following conversion. Write a mechanism for the reaction:

Catherine Lemar

Catherine Lemar

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Problem 26

Explain how you could carry out the following conversion. Write a mechanism for the reaction:

Vasu Makani

Numerade Educator

Problem 27

As discussed in Are You Wondering $27-2,$ carbocation rearrangements occur in some substitution and elimination reactions. What elimination product would you expect in the following reaction if no rearrangement of the carbocation occurs? Experiment reveals that the main product is 2,3 -dimethylpent-2-ene. Suggest a mechanism that shows how 2,3 -dimethylpent-2-ene is formed. [Hint: Consider the formation and rearrangement of a carbocation.]

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 28

The molecule in the next column is 2,2 -dimethylpropan-1-ol, a primary alcohol. Because no H atoms are bonded to the $\beta$ carbon atom in this molecule, dehydration seems unlikely. However, when 2,2-dimethylpropan-1-ol is heated with an acid catalyst, 2-methylbut-2-ene is obtained. Suggest a mechanism that shows how 2 -methylbut-2-ene is formed. [Hint: Consider the formation and rearrangement of a carbocation. See Are You Wondering 27-2.]

Vasu Makani

Numerade Educator

Problem 29

Draw the structures of the products of each of the following reactions:
(a) propene + hydrogen (Pt, heat)
(b) butan-2-ol + heat (in the presence of sulfuric acid)

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 30

Predict the product(s) of the reaction of:
(a) HCl with 2-chloroprop-1-ene
(b) HCN with $\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CH}_{2}$
(c) HCl with $\mathrm{CH}_{3} \mathrm{CH}=\mathrm{C}\left(\mathrm{CH}_{3}\right)_{2}$

Catherine Lemar

Catherine Lemar

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Problem 31

Give the structures of the main organic product(s) in each of the following reactions.

Catherine Lemar

Catherine Lemar

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Problem 32

Give the structure of the main organic product(s) in each of the following reactions:

Catherine Lemar

Catherine Lemar

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Problem 33

Give the major product that forms when $(Z)-3-$ methylpent-2-ene reacts with each of the following reagents: (a) $\mathrm{HI} ;$ (b) $\mathrm{H}_{2}$ in the presence of a platinum catalyst; (c) $\mathrm{H}_{2} \mathrm{O}$ in $\mathrm{H}_{2} \mathrm{SO}_{4} ;$ (d) $\mathrm{Br}_{2}$ in $\mathrm{CCl}_{4}$.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 34

Give the major product that forms when 1 -ethylcyclohex-1-ene reacts with each of the following reagents:
(a) $\mathrm{HI} ;$
(b) $\mathrm{H}_{2}$ in the presence of a platinum catalyst;
(c) $\mathrm{H}_{2} \mathrm{O}$ in $\mathrm{H}_{2} \mathrm{SO}_{4} ;$
(d) $\mathrm{Br}_{2}$ in $\mathrm{CCl}_{4}$.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 35

Sketch the reaction profile for the mechanism depicted in Figure $27-21,$ by assuming the overall reaction is exothermic. Also, experimental evidence suggests that the activation energy for the first step is greater than the activation energy for the second step. Draw structures for the intermediate and transition states.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 36

The chlorination of benzene can be carried out by allowing benzene to react with $\mathrm{Cl}_{2}$ in the presence of $\mathrm{AlCl}_{3} .$ As discussed on page $1305, \mathrm{Cl}_{2}$ and $\mathrm{AlCl}_{3}$ react to form $\mathrm{Cl}^{+} \mathrm{AlCl}_{4}^{-}$. Sketch the reaction profile for the reaction of benzene and $\mathrm{Cl}^{+} \mathrm{AlCl}_{4}^{-}$. Use the same assumptions as in Exercise 35.

Mishal Gul

Numerade Educator

Problem 37

Alkylation of benzene can be accomplished by treating benzene with haloalkane (RX) in the presence of $\mathrm{AlCl}_{3} .$ The reaction is known as a Friedel-Crafts alkylation reaction. (The reaction is named after Charles Friedel, a French chemist, and James M. Crafts, an American chemist, who discovered this method of making alkylbenzenes in $1877 .$ ) An example of a Friedel-Crafts alkylation reaction is shown below: The mechanism for this reaction involves the following steps. First, $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}$ and $\mathrm{AlCl}_{3}$ react in a Lewis acid-base reaction to form an adduct, $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CH}-\mathrm{Cl}-\mathrm{AlCl}_{3},$ in which a chlorine atom is
bonded to both carbon and aluminum. The adduct then dissociates to $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CH}^{+},$ a carbocation, and $\mathrm{AlCl}_{4}^{-}$. The carbocation acts as an electrophile in a reaction with benzene, forming an arenium ion. Finally, a proton is removed from the arenium ion by $\mathrm{AlCl}_{4}^{-},$ yielding an alkylbenzene, $\mathrm{HCl},$ and $\mathrm{AlCl}_{3}$ Write chemical equations for the elementary processes involved in forming cumene and HCl from $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}$ and benzene. Use curved arrows to show the movement of electrons.

Vasu Makani

Numerade Educator

Problem 38

Treating benzene with fuming sulfuric acid yields benzenesulfonic acid, which is formed by the following reaction: The $S O_{3}$ that participates in the reaction above is formed by the reaction of sulfuric acid molecules: $$2 \mathrm{H}_{2} \mathrm{SO}_{4} \longrightarrow \mathrm{SO}_{3}+\mathrm{HSO}_{4}^{-}+\mathrm{H}_{3} \mathrm{O}^{+}$$ The reaction of benzene and $\mathrm{SO}_{3}$ to give benzenesulfonic acid involves the following elementary processes. $\mathrm{SO}_{3}$ acts as an electrophile in a reaction with benzene, forming an arenium ion. A proton is then transferred from the arenium ion to $\mathrm{HSO}_{4}^{-}$, forming the benzenesulfonate ion, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{3}^{-},$ and $\mathrm{H}_{2} \mathrm{SO}_{4}$. Finally, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{3}^{-}$
is protonated by $\mathrm{H}_{3} \mathrm{O}^{+}$ to give benzenesulfonic acid and a water molecule. Write balanced chemical equations for these elementary processes, using curved arrows to show the movement of electrons.

Vasu Makani

Numerade Educator

Problem 39

Predict the main product(s) of (a) the mononitration of chlorobenzene; (b) the monosulfonation of nitrobenzene; (c) the monochlorination of 1-methyl2-nitrobenzene.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 40

Predict the main product(s) of (a) the mononitration of benzoic acid; (b) the monosulfonation of phenol;
(c) the monobromination of 2 -nitrobenzaldehyde.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 41

What is major product expected from the monobromination of 2,2,3 -trimethylpentane?

Catherine Lemar

Catherine Lemar

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Problem 42

What are the major products expected from the monobromination of methylcyclohexane? What about monochlorination?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 43

(a) Write the initiation, propagation, and termination steps involved in the monofluorination of 2,3-dimethylbutane to give 1-fluoro-2,3-dimethylbutane. (b) Explain why in the monofluorination of $2,3-$ dimethylbutane the major product is $1-$ fluoro- $2,3-$ dimethylbutane, not 2 -fluoro- 2,3 -dimethylbutane.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 44

Write the initiation, propagation, and termination steps involved in the monobromination of $2,3-$ dimethylbutane to give 2 -bromo- 2,3 -dimethylbutane.

Vasu Makani

Numerade Educator

Problem 45

In referring to the molecular mass of a polymer, we can speak only of the average molecular mass. Explain why the molecular mass of a polymer is not a unique quantity, as it is for a substance like benzene.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 46

Explain why Dacron is called a polyester. What is the percent oxygen, by mass, in Dacron?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 47

Nylon 66 is produced by the reaction of hexane- $1,6-$ diamine with adipic acid, HOOC(CH $_{2}$ ) $_{4}$ COOH. A different nylon polymer is obtained if sebacoyl chloride is substituted for the adipic acid. What is the basic repeating unit of this nylon structure?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 48

Would you expect a polymer to be formed by the reaction of terephthalic acid with ethyl alcohol in place of ethylene glycol? With glycerol in place of ethylene glycol? Explain.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 49

Starting with acetylene as the only source of carbon, together with any inorganic reagents required, devise a method to synthesize acetaldehyde.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 50

Starting with acetylene as the only source of carbon, together with any inorganic reagents required, devise a method to synthesize 1,1,2,2 -tetrabromoethane.

Vasu Makani

Numerade Educator

Problem 51

How would you synthesize $(E)$ - and $(Z)$ -hept-3-ene from acetylene and any other chemicals?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 52

How would you synthesize ( $R$ )-butan-2-amine from (S)-butan-2-ol?

Vasu Makani

Numerade Educator

Problem 53

The azide anion is a nucleophile and when attached to a carbon atom, undergoes reduction to the amino group and free nitrogen. Suggest a method of preparation of the primary amine propanamine.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 54

The cyanide anion is a nucleophile and when attached to a carbon atom, is reduced to a primary amine. Suggest a method of preparing propanamine from chloroethane.

Vasu Makani

Numerade Educator

Problem 55

Draw a structure to represent the principal product of each of the following reactions:
(a) pentan-1-ol + dichromate ion (acid solution)
(b) butyric acid $+$ ethanol (acid solution)
(c) 2-methylbut-1-ene + HBr

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 56

Predict the products of the monobromination of
(a) $m$ -dinitrobenzene; (b) aniline; (c) $p$ -bromoanisole.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 57

Write the formulas of the products formed from the reaction of propene with each of the following substances: (a) $\mathrm{H}_{2}$ with Pt catalyst; (b) $\mathrm{Cl}_{2} ;$ (c) HCl;
(d) $\overline{H_{2} O}$ (in acid).

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 58

Write the formulas of the products formed from the reaction of but-2-ene with each of the following substances: (a) $\mathrm{H}_{2}$ with Pt catalyst; (b) $\mathrm{Cl}_{2} ;$ (c) HCl;
(d) $\mathrm{H}_{2} \mathrm{O}$ (in acid).

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 59

Which of the following species gives the reaction indicated? Write the structures of the reaction products.
(a) reacts with dilute HCl
(b) hydrolyzes
(c) neutralizes dilute $\mathrm{NaOH}$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 60

Which of the following species gives the reaction indicated? Write the structures of the reaction products.
(a) neutralizes dilute HCl
(b) hydrolyzes
(c) neutralizes dilute $\mathrm{NaOH}$

Vasu Makani

Numerade Educator

Problem 61

Write the formulas of the products expected to form in the following situations. If no reaction occurs, write N.R.
(a) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow$
(b) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{N}(\mathrm{aq})+\mathrm{HBr}(\mathrm{aq}) \longrightarrow$
(c) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{3}+(\mathrm{aq})+\mathrm{H}_{3} \mathrm{O}^{+}(\mathrm{aq}) \longrightarrow$
(d) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{3}^{+}(\mathrm{aq})+\mathrm{OH}^{-}(\mathrm{aq}) \longrightarrow$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 62

Write the formulas of the products expected to form in the following situations. If no reaction occurs, write N.R.
(a) $[\mathrm{NH}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow$
(b) $\left(\mathrm{CH}_{3}\right)_{4} \mathrm{N}^{+}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow$
(c) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2}(\mathrm{aq})+\mathrm{OH}^{-}(\mathrm{aq}) \longrightarrow$
(d) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{NH}^{+}+\mathrm{OH} \rightarrow$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 63

To prepare butan-2-one, which of these compounds would you oxidize: propan-2-ol, butan-1-ol, butan-2ol, or 2 -methylpropan- 2 -ol? Explain.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 64

Indicate the principal product(s) you would expect in
(a) treating $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}=\mathrm{CH}_{2}$ with dilute $\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq})$
(b) exposing a mixture of chlorine and propane gases to ultraviolet light; (c) heating a mixture of isopropyl alcohol and benzoic acid; (d) oxidizing butan-2-ol with $\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}$ in acidic solution.

Vasu Makani

Numerade Educator

Problem 65

Match the following compounds with the chemical properties given below. Write the structure of the products of the reactions described in (a) to (e). (a) is easily oxidized
(b) neutralizes $\mathrm{NaOH}(\mathrm{aq})$
(c) forms an ester with ethanol
(d) can be oxidized to a carboxylic acid
(e) can be reduced to an alcohol

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 66

Match the following compounds with the chemical properties given below. Write the structure of the products of the reactions described in (a) to (e).
(a) neutralizes HCl(aq)
(b) neutralizes NaOH(aq)
(c) forms an amide with ethanoic acid
(d) reacts with ammonia
(e) reacts with $\mathrm{CN}^{-}(\text {aq })$

Vasu Makani

Numerade Educator

Problem 67

Write the structures of the isomers you would expect to obtain in the mononitration of $m$ -methoxybenzaldehyde:

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 68

In the chlorination of $\mathrm{CH}_{4}$, some $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}$ is obtained as a product. Explain why this should be so.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 69

The three isomeric tribromobenzenes, I, II, and III, when nitrated, form three, two, and one mononitrotribromobenzenes, respectively. Assign correct structures to I, II, and III.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 70

Write the name and structure of the benzene derivatives described below.
(a) Formula: $\mathrm{C}_{8} \mathrm{H}_{10}$; forms three monochlorination products when treated with $\mathrm{Cl}_{2}$ and $\mathrm{FeCl}_{3}$
(b) Formula: $\mathrm{C}_{9} \mathrm{H}_{12}$; forms one monochlorination product when treated with $\mathrm{Cl}_{2}$ and $\mathrm{FeCl}_{3}$
(c) Formula: $\mathrm{C}_{9} \mathrm{H}_{12}$; forms four monochlorination products when treated with $\mathrm{Cl}_{2}$ and $\mathrm{FeCl}_{3}$

Vasu Makani

Numerade Educator

Problem 71

For the monochlorination of hydrocarbons, the following ratio of reactivities has been found: $3^{\circ}>2^{\circ}>$
$1^{\circ}, \quad 4.3: 3: 1 .$ How many different monochloro derivatives of 2 -methylbutane are possible, and what percentage of each would you expect to find?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 72

The cyanide anion is a nucleophile and, when attached to a carbon atom, undergoes hydrolysis under basic conditions to the carboxylate anion. Suggest a method of preparing sodium butanoate from chloropropane. How can sodium butanoate be converted into butanoic acid?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 73

The iodide ion cannot displace the $-\mathrm{OH}$ group in ethanol, but excess HI will react to produce ethyl iodide. Explain.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 74

Starting with the compounds chloromethane, chloroethane, sodium azide, sodium cyanide, and a reducing agent, suggest how the following compounds could be synthesized.
(a) $N$ -methylpropanamide
(b) ethyl ethanoate
(c) $N$ -methylethanamine
(d) tetramethylammonium chloride

Nicholas Sacco

Numerade Educator

Problem 75

Predict and name the product(s) obtained from the following reaction. Write out the mechanism for the reaction and use curved arrows to show the movement of electrons.
$$\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}=\mathrm{CH}_{2} \stackrel{\mathrm{H}_{3} \mathrm{SO}_{4} \mathrm{H}_{2} \mathrm{O}}{\longrightarrow}$$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 76

Predict and name the product(s) obtained from the following reaction. Write out the mechanism for the reaction and use curved arrows to show the movement of electrons.

Nicholas Sacco

Numerade Educator

Problem 77

Starting with benzene and methane, and suitable inorganic reagents, suggest how the following compound might be synthesized. [Hint: See Exercise 37 for a description of how an alkyl group can be added to the benzene ring.]

Vasu Makani

Numerade Educator

Problem 78

The reduction of aldehydes and ketones with a suitable hydride-containing reducing agent is a good way of synthesizing alcohols. This approach would be even more effective if, instead of a hydride, we could use a source of nucleophilic carbon. Attack by a carbon atom on a carbonyl group would give an alcohol and simultaneously form a carbon-to-carbon bond. How can we make a $\mathrm{C}$ atom in an alkane nucleophilic? This was achieved by Victor Grignard, who created the organometallic reagent $\mathrm{R}-\mathrm{MgBr},$ with the following reaction in diethyl ether:
$$\mathrm{R}-\mathrm{Br}+\mathrm{Mg} \longrightarrow \mathrm{R}-\mathrm{MgBr}$$
The Grignard reagent is rarely isolated. It is formed in solution and used immediately in the desired reaction. The alkylmetal bond is highly polar, with the partial negative charge on the $\mathrm{C}$ atom, which makes the C atom highly nucleophilic. The Grignard reagent $(\mathrm{R}-\mathrm{MgBr})$ can attack a carbonyl group in an aldehyde or ketone as follows: Addition of dilute aqueous acid solution to the metal alkoxide furnishes the alcohol. The important synthetic consequence of this procedure is that we have prepared a product with more carbon atoms than present in the starting material. A simple starting material can be transformed into a more complex molecule.
(a) What is the product of the reaction between methanal and the Grignard reagent formed from 1-hromohutane after the addition of dilute acid?
(b) By using a Grignard reagent, devise a synthesis for hexan-2-ol.
(c) By using a Grignard reagent, devise a synthesis for 2 -methylhexan- 2 -ol.
(d) Grignard reagents can also be formed with aryl halides, such as chlorobenzene. What would be the product of the reaction between the Grignard reagent of chlorobenzene and propanone? Can you think of an alternative synthesis of this product, again using a Grignard reagent?
(e) The basicity of the $C$ atom bound to the magnesium in the Grignard reagent can be used to make Grignard reagents of terminal alkynes. Write the equation of the reaction between ethylmagnesium bromide and hex-1-yne. [Hint: Ethane is evolved.]
(f) By using a Grignard reagent, suggest a synthesis for hept-2-yn-1-ol.

Nicholas Sacco

Numerade Educator

Problem 79

Explain the important distinctions between each pair of terms: (a) nucleophilic substitution and electrophilic aromatic substitution; (b) addition and elimination; (c) $\mathrm{S}_{\mathrm{N}} 1$ and $\mathrm{S}_{\mathrm{N}} 2 ;$ (d) $\mathrm{E} 1$ and $\mathrm{E} 2$.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 80

Explain the important distinctions between each pair of terms: (a) base and nucleophile; (b) $\alpha$ carbon and $\bar{\beta}$ carbon; (c) polar protic solvent and polar aprotic solvent; (d) carbocation and radical.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 81

(a) Which of the nucleophiles $\mathrm{CN}^{-}$ or $\mathrm{Cl}^{-}$ reacts faster with $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{I}$ in an $\mathrm{S}_{\mathrm{N}} 2$ reaction?
(b) Which of the substrates, $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{2} \mathrm{I}$
or $\mathrm{CH}_{3}$ I, reacts faster with $\mathrm{OH}^{-}$ in an $\mathrm{S}_{\mathrm{N}}$ 2 reaction?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 82

Which of the following is the strongest nucleophile
(a) $\mathrm{H}_{2} \mathrm{O} ;$ (b) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$
for an $S_{N} 2$ reaction? (c) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{O}^{-} ;$ (d) $\mathrm{CH}_{3} \mathrm{CO}_{2}^{-} ;$ (e) $\mathrm{CH}_{3} \mathrm{S}^{-}$.

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 83

Which of the following reactions would give a better yield of $\mathrm{CH}_{3} \mathrm{OCH}\left(\mathrm{CH}_{3}\right)_{2} ?$ Explain. $$\begin{array}{l}
\mathrm{CH}_{3} \mathrm{ONa}+\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHI} \longrightarrow \mathrm{CH}_{3} \mathrm{OCH}\left(\mathrm{CH}_{3}\right)_{2}+\mathrm{NaI} \\
\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHONa}+\mathrm{CH}_{3} \mathrm{I} \longrightarrow \mathrm{CH}_{3} \mathrm{OCH}\left(\mathrm{CH}_{3}\right)_{2}+\mathrm{NaI}
\end{array}$$

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 84

What is the major elimination product obtained in the following reactions?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 85

What is the major organic product obtained in the following reactions?

Catherine Lemar

Catherine Lemar

Numerade Educator

Problem 86

When $\left(\mathrm{CH}_{3} \mathrm{CH}_{2}\right)_{3} \mathrm{CBr}$ is added to $\mathrm{CH}_{3} \mathrm{OH}$ at room
temperature, the major product is $\mathrm{CH}_{3} \mathrm{O}\left(\mathrm{CH}_{2} \mathrm{CH}_{3}\right)_{3}$
and a minor product is $\mathrm{CH}_{3} \mathrm{CH}=\mathrm{C}\left(\mathrm{CH}_{2} \mathrm{CH}_{3}\right)_{2} .$ Write
out the mechanisms for the reactions leading to these products and use curved arrows to show the movement of electrons.

Nicholas Sacco

Numerade Educator