Bruice Organic Chemistry 6e

7/22/2019 Bruice Organic Chemistry 6e

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Organic Chemistry, 6e (Bruice)

Chapter 1 Electronic Structure and Bonding Acids and Bases

1) Atoms with the same number of protons but different numbers of neutrons are called________.

Answer: isotopes

Section: 1-1

2) Which of the following elements does this electronic configuration represent?

1s22s22p

A) !") #

#) $

%) Al&) '

Answer: A

Section: 1-2

() ow man* unpaired electrons are present in the isolated carbon atom +atomic number , )?

A) none

") one#) two

%) three

&) fourAnswer: #

Section: 1-2

) Which of the following is the electronic configuration of the element !e?

A) 1s2

2s22p

(s

2(p

s

2(d

") 1s22s22p(s2(p/(d

#) 1s22s22p/(s2(ps2(d

%) 1s22s22p(s2(ps2d

&) 1s22s22p(s2(ps2p

Answer: ASection: 1-2

) 0he atomic number of boron is . 0he correct electronic configuration of boron is:

A) 1s22s(

") 1s22p(

#) 1s22s22p1

%) 2s22p(

&) 1s22s2(s1

Answer: #

Section: 1-2

1


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) Which of the following statements correctl* describes the third electron shell that surroundsthe nucleus of an atom?

A) 0he third shell contains onl* sand patomic orbitals.

") 0he maimum number of electrons that can occup* the third shell is 1/.#) 0he total number of atomic orbitals present in the third shell is 1.

%) 0he third shell can contain forbitals.

&) All third shell elements must hae d electrons.Answer: "

Section: 1-2

3) Ar4 564 #l-are isoelectronic elements +elements with the same number of electrons). Whatorbital does the last electron occup*?

Answer: (p orbital

Section: 1-2

/) 0he compound meth*lamine4 #($24 contains a #-$ bond. 7n this bond4 which of the

following best describes the charge on the nitrogen atom?

A) 61") slightl* positie

#) uncharged

%) slightl* negatie

&) -1Answer: %

Section: 1-(

8) Which of the compounds below hae bonds that are predominantl* ionic?

A) 5#l") #!

#) $(%) both A and "

&) both " and #

Answer: ASection: 1-(

19) What t*pe of bonding is most important in #(#2#2#2#2#(?

A) ionic") h*drogen

#) coalent

%) polar

Answer: #Section: 1-(

2


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11) Which of the following contain+s) polar coalent bonds?A) $(

") $a2'

#) 2

%) 5!

&) both A and #

Answer: ASection: 1-(

12) Which of the following coalent bonds has the largest dipole moment?

A) #-#

") #-

#) #-'%) -$

&) -!

Answer: &Section: 1-(

1() sing the s*mbol ;6and ;-4 indicate the direction of the polarit* in the indicated bond.

Answer:

Section: 1-(

1) #oalent bonds ma* be polar or nonpolar. What propert* of the atoms forming a gien bond

determines this?

Answer: electronegatiit*Section: 1-(

1) , e d4 where > is the bond dipole moment4 eis the amount of charge which is

separated4 and dis the distance oer which the charge is separated.

Section: 1-(

(


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1) 0he formal charge on nitrogen in the compound below is ________.

A) 62") 61

#) 9

%) -1&) -2

Answer: "

Section: 1-

13) Which of the following is the most li@el* electronic structure for #22?

A)

")

#)

%) ##

&)

Answer: %

Section: 1-


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1/) Which of the following structures4 including formal charges4 is correct for diaomethane4#2$2?

A) :#2$$:

")

#)

%)

&)

Answer: %

Section: 1-

18) What are the formal charges on nitrogen and the starred o*gen atom in the following

molecule?

A) $ , -14 ' , 9") $ , 614 ' , -1#) $ , 614 ' , 61

%) $ , -14 ' , -1

&) $, 614 ' , 9

Answer: &Section: 1-


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29) %raw the 5e@ulB structure for each of the following:

a. #(#2' b. #(#' c. +#()(#6

Answer:

Section: 1-

21) 0he 5e@ulB structure of pentane is shown below. %raw the condensed structural formulawhich corresponds to this Cewis structure.

Answer: #(+#2)(#(

Section: 1-

22) %raw condensed structures for the four compounds with formula #(8$.

Answer:

#(#2#2$2

#(#2$#(

+#()2#$2

+#()($

Section: 1-

2() Write a Cewis structure for the molecule gien and show all formal charges.#2#'

Answer:

Section: 1-


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2) &pand the condensed structure below to show the coalent bonds and the lone-pair

electrons.

+#()2##2#'

Answer:

Section: 1-

2) %raw the Cewis structure for #($26.

Answer:

Section: 1-

2) ow man* distinct and degenerate p orbitals eist in the second electron shell4 where n , 2?A) 9

") 1

#) 2

%) (&)

Answer: %

Section: 1-

23) %raw the shape of a 2p orbital.

Answer:

Section: 1-

2/) #onsider the interaction of two h*drogen 1s atomic orbitals of the same phase. Which of thestatements below is an incorrectdescription of this interaction?

A) A sigma bonding molecular orbital is formed.

") 0he molecular orbital formed is lower in energ* than a h*drogen 1s atomic orbital.#) 0he molecular orbital formed has a node between the atoms.

%) 0he molecular orbital formed is c*lindricall* s*mmetric.

&) A maimum of two electrons ma* occup* the molecular orbital formed.

Answer: #Section: 1-

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28) "oth sigma +D) and pi +E) bonds can be formed b* oerlapping p orbitals. %escribe thedifference.

Answer: Sigma bonds are formed from the oerlap of atomic orbitals along a circular ais of

s*mmetrical nature4 i.e.4 head-on oerlap. All single bonds are sigma bonds.


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() What @ind of molecular orbital +D4 DF4 E4 or EF) results when the two atomic orbitals shownbelow interact in the manner indicated?

Answer: EF

Section: 1-

() #hoose the correct h*bridiation for the atom indicated in the molecule below.

#(#2#2#(

G

A) sp

") sp2

#) sp(

%) none of the aboe

Answer: #Section: 1-3

() What orbitals are used to form the coalent bonds in butane +#(#2#2#()?

Answer: 0he carbon-carbon D bonds are formed b* the oerlap of two carbon sp(h*brid atomic

orbitals. 0he carbon-h*drogen D bonds are formed b* the oerlap of a carbon sp(h*brid atomicorbital and a h*drogen s orbital.

Section: 1-3

(3) Which carbon+s) in the following molecule is +are) sp h*bridied?

A) carbon 1") carbon 2

#) carbons 14 (

%) carbons &) carbons 4

Answer: &

Section: 1-8

8


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(/) Which of the following is an sp2h*bridied carbon?

A)

") H #(

#)

%) A and "&) A4 " and #

Answer: A

Section: 1-19

(8) What is the predicted shape4 bond angle4 and h*bridiation for 6#(?

A) trigonal planar4 129I4 sp2

") trigonal planar4 129I4 sp(

#) trigonal planar4 198.I4 sp2

%) trigonal p*ramidal4 129I4 sp2

&) trigonal p*ramidal4 198.I4 sp2


9) What orbitals oerlap to create the -# bond in #(6?

A) sp(-sp(

") sp2-sp(

#) s-p%) s-sp2

&) s-sp(

Answer: %

Section: 1-19

1) 0he lone-pair electrons of the meth*l anion occup* a+n) ________ orbital.

A) s") p

#) sp

%) sp2

&) sp(

Answer: &Section: 1-19

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2) Which of the following is closest to the #-'-# bond angle in #(-'-#(?

A) 1/9I

") 129I

#) 198.I

%) 89I&) 19I

Answer: #

Section: 1-11

() &ach lone pair of electrons on the ' atom in methanol +# (') occupies a+n) ________

orbital.

A) s") p

#) sp

%) sp2

&) sp(

Answer: &

Section: 1-11

) 0he $- single bond in meth*l amine +#($2) is a ________ bond formed b* the oerlap

of a+n) ________ orbital on $ and a+n) ________ orbital on .

A) DJ sp2J s

") D J sp(J s

#) E J sp(J s

%) E J sp2J p

&) E J p J pAnswer: "

Section: 1-12

) 0rieth*lamine K+#(#2)($L is a molecule in which the nitrogen atom is ________

h*bridied and the #$# bond angle is ________.

A) sp24 M198.I

") sp24 N198.I

#) sp(4 M198.I

%) sp(4 N198.I

&) sp4 198.IAnswer: %

Section: 1-12

11


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) 0he $- bond in the ammonium ion4 $64 is formed b* the oerlap of what two orbitals?

A) sp(-sp(

") sp(-sp2

#) sp2-sp2

%) sp2-s

&) sp(-sAnswer: &

Section: 1-12

3) Among the h*drogen halides4 the strongest bond is found in ________ and the longest bond

is found in ________.

A) !4 !") !4 7

#) 74 !

%) 74 7&) #l4 "r

Answer: "

Section: 1-1(

/) Which bond in the following molecule is the shortest?

A) bond 1

") bond 2

#) bond (%) bond

&) bond Answer: &

Section: 1-1

8) Which of the following species hae tetrahedral bond angles?

A) A4 % and &

") A4 %4 & and !#) A and &

%) % onl*

&) A4 " and &Answer: "

Section: 1-1

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9) 0he carbon-carbon double bond in ethene is ________ and ________ than the carbon-carbontriple bond in eth*ne.

A) strongerJ shorter

") strongerJ longer#) wea@erJ shorter

%) wea@erJ longer

&) strongerJ more polarAnswer: %

Section: 1-1

1) What is the #$$ bond angle in the compound shown below?

A) O9I

") O89I#) O119I

%) O129I

&) O1/9IAnswer: %

Section: 1-1

2) %raw the structure of a molecule which contains onl* carbon and h*drogen atoms +onl* three

of which are carbon) and in which two of the carbons are sp2h*bridied and the other is sp

h*bridied.

Answer: 2###2

Section: 1-1

() Wh* is the # bond in ethene +2##2) shorter and stronger than the # bond in

ethane+#(#()?

Answer: 0he length and strength of a # bond depends on the h*bridiation of the carbon

atom. 0he more scharacter in the h*brid orbital used b* carbon to form the bond4 the shorter andstronger the bond. 0his is because an sorbital is closer to the nucleus than is a p. &thene uses

carbon sp2h*brid orbitals +1P( scharacter) to ma@e its carbon-h*drogen bonds while ethane uses

carbon sp(+1P scharacter).

Section: 1-1

) Which of the following molecules does not ehibit a net dipole moment of ero?

A) #'2

") #

#) ##l

%) 2'

&) S'(

Answer: %

1(


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Section: 1-1

) Which of the following molecules has a net dipole moment of ero?A)

")

#)

%)

&)

Answer: "

Section: 1-1

) Which of the following molecules has the smallest dipole moment?

A) "r2

") $(#) #l

%) "r

&) 7


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3) "!(has a dipole moment of ero.


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1) 0he conQugate acid of 2' is:

A) ('-

") ('

#) ('6

%) '-

&) 2'6


2) Which of the following ions is the strongest acid?

A) -

") '-

#) S'-

%) 2'

&) ('6


() Which species act as bases in the following reaction?

A) 1 and 2

") ( and

#) 2 and %) 1 and (

&) 2 and (Answer: #

Section: 1-1

) What is the conQugate acid of $(?

A) 6$(

") -$

#) 6$

%)-$2

&) 6$2

Answer: #

Section: 1-1

1


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) What is the conQugate acid of #($2?

A) #($(6

") #($-

#) $6

%) $2-


) What is the conQugate base of #($2?

A) #($(6

") #($-

#) $6

%) $2-

Answer: "

Section: 1-1

3) Rie the conQugate acid and the conQugate base for S'-.

Answer: conQugate acid: 2S'

conQugate base: S'2-

Section: 1-1

/) Write a completed e=uation for the acid-base pair shown below.

#'2 6 -$2

Answer: #'2 6 -$2 #'2-6 $(

Section: 1-1

8) What is the p of a 9.1 T solution of #l? +$ote: p5afor #l is -.)

A)

") -

#) 1%) -/

&) -1

Answer: #

Section: 1-13

39) 7f 2' has a p5aalue of 1.3 and ! has a p5aalue of (.24 which is a stronger base4 '-

or !-? &plain.

Answer: '-is a stronger base than !-because ! is a stronger acid than 2'4 and the

stronger the acid the wea@er its conQugate base.

Section: 1-13

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31) Which of the following is the strongest acid?A) #('

") #('26

#) 2$-

%) #($2

&) #($

(

6

Answer: "

Section: 1-21

32) 0he p5a of #(#'' is ./ and the p5a of #'' is (./. Rien this information4 one

@nows that ________.

A) #(#'' completel* ionies in water

") #'' is a wea@er acid than #(#''

#) #''-is a wea@er base than #(#''-

%) #(#'' reacts with '-while #'' does not

&) #'' reacts with '-while #(#'' does notAnswer: #

Section: 1-21

3() Which of the following is the strongest acid?

A) !") 2'

#) :$(%) #&) #('

Answer: A

Section: 1-21

3) Which of the following is the strongest acid?

A) #(#2'

") #('#(

#) #($#(

%) #(##

&) #(##2Answer: A

Section: 1-21

1/


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3) #onsider the set of compounds4 $(4 !4 and 2'. Uan@ these compounds in order of

increasing acidit* and discuss *our rationale.

Answer: $(N 2' N !

When determining relatie acidit*4 it is often useful to loo@ at the relatie basicit* of theconQugate bases. 0he stronger the acid4 the wea@er +more stable4 less reactie) the conQugate base.

7n this case4 one would loo@ at the relatie basicit* of !-4 '-4 and $2-. 0he relatie strengthsof these species can be gauged based on the electronegatiit* of the charged atom in each base.

Since fluorine is the most electronegatie4 !-is the most stable4 least reactie base in the group.

0his means that its conQugate acid4 !4 is the strongest.

Section: 1-21

3) Which of the following is the strongest acid?

A) 7") 77#) 777

%) 7V

&) V


33) &plain wh* :$!(is a wea@er base than :$(.

Answer: !luorine has an electron withdrawing effect that reduces the aailabilit* of the pair ofelectrons on nitrogen. 0hus the basicit* of :$!(is less than that of :$(.

Section: 1-22

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3/) Would *ou predict trifluoromethanesulfonic acid4 #!(S'(4 to be a stronger or wea@er acid

than methanesulfonic acid4 #(S'(? &plain *our reasoning.

Answer: 0rifluoromethanesulfonic acid is a stronger acid. #ompare the strengths of the

conQugate bases and remember that the wea@er the base4 the stronger the conQugate acid. 7n the

case of the trifluoro deriatie4 the presence of the highl* electronegatie fluorine atoms seresto delocalie the negatie charge to a greater etent. 0his additional delocaliation ma@es

trifluoromethanesulfonate a wea@er base.Section: 1-22

38) Which of the following anions4 #(#"r#'2- or #(#!#'2-is the stronger base?

&plain *our choice.

Answer: #(#"r#'2-is the stronger base. 0he more electronegatie ! atom can more

effectiel* delocalie the negatie charge ia induction. 0his greater delocaliation stabilies

#(#!#'2- relatie to #(#"r#'2-and ma@es it a wea@er base.

Section: 1-22

/9) 0he p5a of #(#'' is ./. 7f the p of an a=ueous solution of #(#'' and#(#''-is ./4 then one @nows ________.

A) #(#'' is completel* ionied

") K#(#''L M K#(#''-L

#) K#(#''L , K#(#''-L

%) K#(#''L N K#(#''-L

&) #(#'' is completel* unionied


/1) When a small amount of heanoic acid K#(+#2)#'24 p5aO./L4 is added to a

separator* funnel which contains the organic solent dieth*l ether and water with a p of 2.94 itis found mainl* in the ________ phase as ________.

A) etherJ #(+#2)#'2-

") waterJ #(+#2)#'2-

#) etherJ #(+#2)#'2

%) waterJ #(+#2)#'2

&) none of the aboe


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/2) When a small amount of heanoic acid K#(+#2)#'24 p5aO./L4 is added to a

separator* funnel which contains the organic solent dieth*l ether and water with a p of 12.94 it

is found mainl* in the ________ phase as ________.

A) etherJ #(+#2)#'2-

") waterJ #(+#2)#'2-

#) etherJ #(+#2)#'2

%) waterJ #(+#2)#'2

&) none of the aboe

Answer: "Section: 1-2

/() At what p will 2 of a compound with a p5a of .( be in its basic form?Answer: ./

Section: 1-2

/) 0he amino acid gl*cine +($6#2#'2) has two acidic s4 one with p5a , 2.( and the

other with p5a,8.9. %raw the structure of the form of gl*cine that predominates at a p of 12.Answer:

Section: 1-2

/) "uffering is used to maintain the p of human blood in the relatiel* narrow 3.( - 3. range.

What acidPbase pair seres to buffer the blood?

A) 2' P '-

") (

'6P 2'

#) 2#'(P #'(-

%) $6P $(

&) #l P #l-

Answer: #

Section: 1-2

/) &plain wh* Al#l(is a Cewis acid.

Answer: A Cewis acid is an electron pair acceptor. Aluminum in Al#l(has an empt* p orbital

that can accommodate the pair of electrons proided b* a Cewis base.

Section: 1-23

21


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/3) Rie the electronic configuration for $-(.

A) 1s22s2

") 1s22s22p(

#) 1s22s22p

%) 1s22s22p

&) 1s22s22p(s1

Answer: %

Section: 1-2

//) Rie the electronic configuration for #a62.

Answer: 1s22s22p(s2(p

Section: 1-2

/8) 7dentif* the least electronegatie atom.

A)

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Bruice Organic Chemistry 6e