Conjugate acid-base pairs

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Avnie R

Cards (59)

How does the concept of conjugate pairs relate to Brønsted-Lowry acids and bases?
They show the acid-base transformation
How can the conjugate acid-base pair be interconverted?
To convert the acid to the conjugate base, remove H+
To convert the base to the conjugate acid, add H+
What is the relationship between the conjugate acid-base pairs shown in the image?
H2O (acid) and OH- (conjugate base) form one conjugate acid-base pair
NH3 (base) and NH4+ (conjugate acid) form the other conjugate acid-base pair
When the acid loses a proton (H+), the conjugate base is formed
When the base gains a proton (H+), the conjugate acid is formed
How do the equilibrium reactions differ between the two conjugate acid-base pairs?
For the H2O/OH- pair: H2O ⇌ H+ + OH-
For the NH3/NH4+ pair: NH3 + H+ ⇌ NH4+
The first is an autoionization reaction of water
The second is a proton transfer reaction between ammonia and a proton
What is the name of the base in the conjugate acid-base pair shown in the image?
OH-
What are the key differences between the two conjugate acid-base pairs shown?
The first pair involves water (H2O) as the acid and hydroxide (OH-) as the base
The second pair involves ammonia (NH3) as the base and ammonium (NH4+) as the conjugate acid
The first pair involves the removal/addition of a single proton (H+)
The second pair involves the removal/addition of an entire ammonium (NH4+) group
How is a conjugate base formed?
When an acid loses a proton
In the Fischer esterification, what bond breaking occurs?
O-H bond in carboxylic acid
What is the definition of proton transfer?
A reversible step where a proton moves
What is a conjugate acid-base pair?
A pair formed by an acid and its base
How is a conjugate acid formed?
When a base gains a proton
In the reaction $HCl +$ $H_{2}O \leftrightarrow H_{3}O^ +$ $+$ $Cl^ -$ , what role does $H_{2}O$ play? 
$H_{2}O$ is the base
What does a proton transfer involve?
A proton moves from one molecule to another
How does the proton transfer step affect the reactivity of the molecule?
The proton transfer makes the carbonyl carbon more electrophilic
This increases its susceptibility to nucleophilic attack
This facilitates the formation of the tetrahedral intermediate
How many bonds are formed and how many bonds are broken in this proton transfer step?
1 bond formed, 1 bond broken
What is a conjugate acid?
A molecule that has gained a proton
In the reaction $HCl +$ $H_{2}O \leftrightarrow H_{3}O^ +$ $+$ $Cl^ -$ , what role does HCl play? 
HCl is the acid
What is the starting material on the left side of the reaction mechanism?
HO-C-O
What are conjugate pairs in Brønsted-Lowry theory?
Species formed after proton transfer
Example: HCl becomes $Cl^ -$
Example: $H_{2}O$ becomes $H_{3}O^ +$
What is the relationship between the conjugate acid-base pairs shown in the image?
H2O (acid) and OH- (conjugate base) form one conjugate acid-base pair
NH3 (base) and NH4+ (conjugate acid) form the other conjugate acid-base pair
When the acid loses a proton (H+), the conjugate base is formed
When the base gains a proton (H+), the conjugate acid is formed
What is a conjugate base?
The original form before proton gain
How can the conjugate acid-base pair be interconverted?
To convert the acid to the conjugate base, remove H+
To convert the base to the conjugate acid, add H+
What is a conjugate acid-base pair?
A pair differing by one H⁺
How do the equilibrium reactions differ between the two conjugate acid-base pairs?
For the H2O/OH- pair: H2O ⇌ H+ + OH-
For the NH3/NH4+ pair: NH3 + H+ ⇌ NH4+
The first is an autoionization reaction of water
The second is a proton transfer reaction between ammonia and a proton
What happens to H₂O in the context of conjugate acids and bases?
H₂O acts as an acid
Produces OH⁻
OH⁻ is its conjugate base
What are the key differences between the two conjugate acid-base pairs shown?
The first pair involves water (H2O) as the acid and hydroxide (OH-) as the base
The second pair involves ammonia (NH3) as the base and ammonium (NH4+) as the conjugate acid
The first pair involves the removal/addition of a single proton (H+)
The second pair involves the removal/addition of an entire ammonium (NH4+) group
What does a Brønsted-Lowry base do?
Accepts a proton
If you add H+ to the conjugate base OH-, what is the resulting compound?
H2O
What are the key steps in the process of proton transfer during Fischer esterification?
Proton moves from carboxylic acid to alcohol
O-H bond in carboxylic acid breaks
O-H bond in alcohol forms
Reaction is reversible, indicated by equilibrium arrows
How do you convert between a conjugate acid-base pair?
To convert from acid to conjugate base, remove H+
To convert from base to conjugate acid, add H+
What is the name of the base in the conjugate acid-base pair shown in the image?
NH3
What does a Brønsted-Lowry acid do?
Donates a proton
What does $HCO_{3}^{-}$ represent in its conjugate pair? 
It is the conjugate base of carbonic acid
What role does NH₃ play in conjugate acids and bases?
NH₃ acts as a base
Produces NH₄⁺
NH₄⁺ is its conjugate acid
What is the relationship between the acid and conjugate base in a conjugate acid-base pair?
The acid donates a proton (H+) to the base
The base accepts the proton from the acid
This forms the conjugate acid-base pair
How does $H_{2}CO_{3}$ relate to $HCO_{3}^{-}$ ? 
Carbonic acid is the conjugate acid of bicarbonate
How does the relationship between conjugate acids and bases work?
It is a reversible relationship based on proton transfer
What does the arrow in conjugate acid-base pairs indicate?
Gain or loss of a proton
What are the components of the conjugate acid-base pair shown in the image?
H2O (acid), OH- (conjugate base), NH3 (base), NH4+ (conjugate acid)
What are the key differences between the acid-base pair and the conjugate acid-base pair shown in the image?
Acid-base pair: H2O (acid), OH- (base)
Conjugate acid-base pair: H2O (acid), OH- (conjugate base), NH3 (base), NH4+ (conjugate acid)
Acid-base pair involves a direct proton transfer
Conjugate acid-base pair involves a reversible proton transfer