What is the Difference Between Conjugate Acid and Conjugate Base?
🆚 Go to Comparative Table 🆚The difference between a conjugate acid and a conjugate base lies in the presence or absence of a proton (H⁺) in their structures. In the Brønsted–Lowry definition of acids and bases, a conjugate acid is formed when a proton is added to a base, and a conjugate base is formed when a proton is removed from an acid.
Here are the key differences between conjugate acids and conjugate bases:
- Formation: A conjugate acid is formed when an acid donates a proton to a base, while a conjugate base is formed when an acid loses a proton during a chemical reaction.
- Structure: A conjugate acid contains one more H atom and one more + charge than the base that formed it. In contrast, a conjugate base contains one less H atom and one more - charge than the acid that formed it.
- Reactivity: The strength of an acid is inversely proportional to the strength of its conjugate base. Similarly, the strength of a base is inversely proportional to the strength of its conjugate acid.
For example, during the reaction of bicarbonate ions with water to create carbonic acid and hydroxide ions:
$$HCO3^- + H2O \longrightarrow H2CO3 + OH^-$$
- Bicarbonate ions (HCO₃⁻) are the base, and after gaining a proton from water, they become carbonic acid (H₂CO₃), which is the conjugate acid of HCO₃⁻.
- Water (H₂O) is the acid in this reaction, and after donating a proton to bicarbonate ions, it becomes the hydroxide ion (OH⁻), which is the conjugate base of H₂O.
Identifying conjugate acid-base pairs is essential in understanding the reactivity of acids and bases in various chemical reactions.
Comparative Table: Conjugate Acid vs Conjugate Base
The difference between a conjugate acid and a conjugate base can be understood through the Brønsted-Lowry theory of acids and bases. A conjugate acid is formed when a proton is added to a base, and a conjugate base is formed when a proton is removed from an acid. Here is a table summarizing the differences between conjugate acids and conjugate bases:
Conjugate Acid | Conjugate Base |
---|---|
Formed when a proton is added to a base | Formed when a proton is removed from an acid |
Can donate a proton (H+) to another substance | Can accept a proton (H+) from another substance |
An example of a conjugate acid is NH4+ (ammonium ion) | An example of a conjugate base is F- (fluoride ion) |
In a reaction, an acid donates a proton to a base, forming a conjugate acid and a conjugate base. For example, in the reaction between hydrofluoric acid (HF) and water (H2O), HF donates a proton to H2O, forming fluoride ion (F-) as the conjugate base and hydrofluoric acid (HF) as the conjugate acid.
- Acid vs Base
- Strong vs Weak Acids vs Bases
- Acid Ionization Constant vs Base Ionization Constant
- Acid vs Acidic
- Alkali vs Base
- Acidity vs Basicity
- Acid vs Alkaline
- Alkali vs Acid
- Concentrated Acid vs Strong Acid
- Acidic Salt vs Basic Salt
- Binary Acids vs Oxyacids
- Basis vs Bases
- Double Displacement vs Acid Base Reactions
- Acid Anhydride vs Basic Anhydride
- Weak Acid vs Dilute Acid
- Weak vs Strong Acid
- Acid Base Reaction vs Precipitation Reaction
- Acid-Base Titration vs Redox Titration
- Carbonic Acid vs Bicarbonate