Deck 2: Acids and Bases: Central to Understanding Organic Chemistry

Question 1

What is the conjugate acid o $\mathrm { NH } _ { 3 }$ ?

A) $+ \mathrm { NH } _ { 3 }$
B) $\text { -NH }$
C) ${ } ^ { + } \mathrm { NH } _ { 4 }$
D) $- \mathrm { NH } _ { 2 }$
E) $+ \mathrm { NH } _ { 2 }$

Answer 1

${ } ^ { + } \mathrm { NH } _ { 4 }$

Question 2

Does water act as an acid or a base in the following reaction? $+ \mathrm { H } _ { 2 } \mathrm { O } \longrightarrow$

A) Acid
B) Base
C) Neither
D) Both

Answer 2

Base

Question 3

What is the conjugate acid of $\mathrm { CH } _ { 3 } \mathrm { NH } _ { 2 }$ ?

A) $\mathrm { CH } _ { 3 } \mathrm { NH } _ { 3 } +$
B) $\mathrm { CH } _ { 3 } \mathrm { NH } ^ { - }$
C) ${ } ^ { + } \mathrm { NH } _ { 4 }$
D) $- \mathrm { NH } 2$

Answer 3

$\mathrm { CH } _ { 3 } \mathrm { NH } _ { 3 } +$

Question 4

Which of the following is not a conjugate acid-base pair?

A) H₂O, HO^-
B) H₂O, H₃O⁺
C) HSO₄-, H₂SO₄
D) -OH, O₂^-
E) NO₃^-, NO₂^-

Question 5

Does acetic acid act as an acid or a base in the following reaction? $+ \mathrm { HO } ^ { \ominus } \longrightarrow$

A) Acid
B) Base
C) Neither
D) Both

Question 6

Does methyl alcohol act as an acid or a base in the following reaction? $+\mathrm{CH}_{3} \mathrm{OH} \longrightarrow$

A) Acid
B) Base
C) Neither
D) Both

Question 7

Which are favored at equilibrium, reactants or products?

A) Reactants
B) Products
C) Both
D) Neither

Question 8

Which of the following is the strongest acid?

A) H^-
B) HO^-
C) HSO₄^-
D) H₂O
E) H₃O⁺

Question 9

What is the product of the following acid-base reaction?

A) $\mathrm { CH } _ { 3 } \mathrm { O } ^ { - } + { } ^ { + } \mathrm { NH } _ { 4 }$
B) $\mathrm { CH } _ { 2 } \mathrm { OH } + { } ^ { + } \mathrm { NH } _ { 3 }$
C) $\mathrm { CH } _ { 3 } \mathrm { OH } _ { 2 } ^ { + } + - \mathrm { NH } _ { 2 }$
D) $\mathrm { CH } _ { 3 } \mathrm { NH } _ { 2 } + \mathrm { H } _ { 2 } \mathrm { O }$
E) CH₄ + Nh₂OH

Question 10

Which of the following is the strongest acid?

A) $\mathrm { CH } _ { 3 } \mathrm { OH }$
B) $\mathrm { CH } _ { 3 } \mathrm { OH } _ { 2 } ^+$
C) $- \mathrm { NH } _ { 2 }$
D) $\mathrm { CH } _ { 3 } \mathrm { NH } _ { 2 }$
E) $\mathrm { CH } _ { 3 } \mathrm { NH } _ { 3 } ^+$

Question 11

Which two species act as bases in the acid-base reaction shown below?

A) 1 and 2
B) 3 and 4
C) 2 and 4
D) 1 and 3
E) 2 and 3

Question 12

Which is a stronger acid, A or B?

A) A
B) B

Question 13

Which are favored at equilibrium, reactants or products?

A) Reactants
B) Products
C) Both
D) Neither

Question 14

Which is a stronger acid, A or B?

A) A
B) B

Question 15

The pK_a of CH₃COOH is 4.8 and the pK_a of HCOOH is 3.80 iven this information, one knows that ________.

A) CH₃COOH completely ionizes in water
B) HCOOH is a weaker acid than CH₃COOH
C) HCOO-
is a weaker base than CH₃COO^-
D) CH₃COOH reacts with HO^- while HCOOH does not
E) HCOOH reacts with HO^- while CH₃COOH does not

Question 16

What is the conjugate base of $\mathrm { CH } _ { 3 } \mathrm { NH } _ { 2 }$ ?

A) $\mathrm { CH } _ { 3 } \mathrm { NH } _ { 3 } +$
B) $\mathrm { CH } _ { 3 } \mathrm { NH } ^ { - }$
C) ${ } ^ { + } \mathrm { NH } _ { 4 }$
D) $- \mathrm { NH } _ { 2 }$

Question 17

Which of the following is the strongest acid?

A) CH₃CH₂OH
B) CH₃OCH₃
C) CH₃NHCH₃
D) $\mathrm { CH } _ { 3 } \mathrm { C } \equiv \mathrm { CH }$
E) CH₃CH=CH₂

Question 18

The conjugate acid of H₂O is ________.

A) H₃O^-
B) H₃O
C) H₃O⁺
D) HO^-
E) H₂O⁺

Question 19

What is the pH of a 0.1 M solution of HCl?

A) 6
B) -6
C) 1
D) -8
E) -1

Question 20

Which of the following is the strongest acid?

A) HF
B) H₂O
C) NH₃
D) CH₄
E) CH₃OH

Question 21

Draw the conjugate base of the following compound: (CH₃)₂CHOH

Question 22

Draw a resonance contributor and the resonance hybrid for HOCO₂^-.

Question 23

Which of the following has the highest pK_a ?

A) CH₃CH₃
B) HCCH
C) CH₂CH₂
D) CH₃OH
E) CH₃NH₂

Question 24

HA is an acid with a pK_a=4.5 hich of the following statements about an aqueous solution of HA is true?

A) At pH=4.5 , the solution contains more H-A than A-
B) At pH=4.5 , the solution contains more A- than H-A.
C) At pH=3.5 , the solution contains more A- and HA.
D) At pH=6.5 , the solution contains much more HA than A-.
E) At pH=4.5 , the solution contains about the same amount of A- and HA.

Question 25

Which of the following carboxylic acids is the strongest acid?

A) ICH₂COOH
B) BrCH₂COOH
C) CH₃COOH
D) FCH₂COOH
E) ClCH₂COOH

Question 26

When a small amount of CH₃(CH₂)₄ CO₂H (pKa~4.8) is added to a separatory funnel that contains ether and water with a pH=12.0 is found mainly in the ________ layer as ________.

A) ether; CH₃(CH₂)₄)CO₂^-
B) water; CH₃(CH₂)₄CO₂^-
C) ether; CH₃(CH₂)₄CO₂H
D) water; CH₃(CH₂)₄CO₂H
E) none of the above

Question 27

H₂O has a pK_a value of 15.7 and HF has a pK_a value of 3.2, which is a stronger base HO- or F-? Explain.

Question 28

When a small amount of CH₃(CH₂)₄CO₂H, (pKa~ 4.8) is added to a separatory funnel that contains ether and water with a pH=2.0 is found mainly in the ________ layer as ________.

A) $\text { ether; } \mathrm { CH } _ { 3 } \left( \mathrm { CH } _ { 2 } \right) 4 \mathrm { CO } _ { 2 } ^ { - }$
B) $\text { water; } \mathrm { CH } _ { 3 } \left( \mathrm { CH } _ { 2 } \right) 4 \mathrm { CO } _ { 2 } ^ { - }$
C) $\text { ether; } \mathrm { CH } _ { 3 } \left( \mathrm { CH } _ { 2 } \right) _ { 4 } \mathrm { CO } _ { 2 } \mathrm { H }$
D) $\text { water; } \mathrm { CH } _ { 3 } \left( \mathrm { CH } _ { 2 } \right) _ { 4 } \mathrm { CO } _ { 2 } \mathrm { H }$
E) none of the above

Question 29

The amino acid (H₃N⁺CH₂CO₂H) has two acidic H's, one with a pK_a=2.34 nd the other with a pK_a=9.60 raw the structure of the amino acid that predominates at pH=12.

Question 30

Is the stronger base? Explain your choice.

Question 31

What is the conjugate acid and the conjugate base of ?

Question 32

A buffer is used to maintain the pH of human blood a at ~ 7.4 hich acid/base pair buffers the blood?

A) H₂O/ HO-
B) H₃O+ /H₂O
C)H₂CO₃/HCO₃^-
D) NH₄⁺ /NH₃
E) HCl/Cl^-

Question 33

Which of the following has the highest

A) CH₃NH₂
B) CH₃OH
C) CH₃COOH
D) H₂O
E) CH₃NH₃⁺

Question 34

Explain why NF₃ is a weaker base than NH₃.

Question 35

The pK_a of CH₃COOH is 4.8 . If the pH of an aqueous solution of CH₃COOH CH₃COO^- is 4.8, then one knows ________.

A) CH₃COOH is completely ionized
B) $\left[ \mathrm { CH } _ { 3 } \mathrm { COOH } \right] > \left[ \mathrm { CH } _ { 3 } \mathrm { COO } ^ { - } \right]$
C) $\left[ \mathrm { CH } _ { 3 } \mathrm { COOH } \right] = \left[ \mathrm { CH } _ { 3 } \mathrm { COO } ^ { - } \right]$
D) $\left[ \mathrm { CH } _ { 3 } \mathrm { COOH } \right] < \left[ \mathrm { CH } _ { 3 } \mathrm { COO } ^ { - } \right]$
E) $\mathrm { CH } _ { 3 } \mathrm { COOH }$ is completely unionized

Question 36

Rank NH₃, HF , and H₂O in order of increasing acidity and explain your rationale.

Question 37

Write the products of the following acid-base reaction:

Question 38

1. What form of the compound, H , predominates in a
solution with