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15-1 objectives
• List 5 general properties of aqueous acids and bases
• Name common binary acids and oxyacids
• List 5 common industrial and laboratory acids and give 2 properties of each
• Define Arrhenius acids and bases
• Explain the difference between strong
and weak acids and bases
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Properties of Acids
1. Taste sour
2. Change the color of pH indicators
(turn blue litmus paper red)
3. React with active metals to produce hydrogen gas
4. React with bases to produce salts and water
5. Conduct an electric current
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Properties of Bases
1. Taste bitter
2. Change the color of acid-base indicators
(turn red litmus paper blue)
3. Feel slippery
4. React with acids to produce salts and water
5. Conduct an electric current
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Commonly Used AcidsSulfuric acid (H2SO4)
dehydrating agent; batteries; metals, paper; dyes, paints & detergents
Nitric acid (HNO3)stains proteins yellow; very smelly; explosives
Phosphoric acid (H3PO4)fertilizer; ceramics; detergents; flavoring
Hydrochloric acid (HCl)“pickling” metals; food processing; pools; cleaning masonry
Acetic acid (CH3COOH)smelly; vinegar; freezes at 17oC; plastics; fungicide
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Arrhenius Acid & Bases
Arrhenius acid – increases the concentration of hydrogen ions in aqueous solution
HNO3(l) + H2O(l) H3O+(aq) + NO3
-(aq)
The H3O+ ion is called the hydronium ion
Arrhenius base – increases the concentration of hydroxide ions in aqueous solutions
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Strong AcidsStrong acids ionize completely in aqueous
solutions and are strong electrolytes
Examples:
H2SO4
HClO4
HCl
HNO3
HBr
HI
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Weak Acids
Do not ionize completely and are weak electrolytes
Examples:
H3PO4
CH3COOH
H2CO3
H2S
HCN
Clip
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Strong Bases
A strong base completely dissociates in water to produce OH- ions
Solutions are called alkaline
Examples:
NaOH
KOH
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Weak Bases
Weak bases do not dissociate completely in solution
Example:
NH3
C6H5NH2 (aniline)
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15-2 Objectives
• Define and recognize Brønsted-Lowry acids and bases
• Define a Lewis acid and a Lewis base
• Name compounds that are acids under the Lewis definition but are not acids under the Brønsted-Lowry definition
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Brønsted-Lowry Acids
• A molecule or ion that is a proton donor is Brønsted-Lowry acid
Example:
HCl dissolved in ammonia
HCl dissolved in water
H2O dissolved in ammonia
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Brønsted-Lowry Bases
• A molecule or ion that accepts a proton is a Brønsted-Lowry base
Example:
HCl dissolved in ammonia
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Monoprotic Acids
Monoprotic acids can donate only one proton
Example:
HCl(g) + H2O(l) H3O+(aq) + Cl-(aq)
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Polyprotic Acids
Polyprotic acids can donate more than one proton
Example:
H2SO4(l) + H2O(l) H3O+(aq) + HSO4
-(aq)
HSO4-(aq) + H2O(l) H3O
+(aq) + SO42-(aq)
This is a diprotic acid (2 ionizations)
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Lewis Acids and Bases
An atom, ion, or molecule that accepts an electron pair to form a covalent bond is a Lewis acid
An atom, ion, or molecule that donates an electron pair to form a covalent bond is a Lewis base
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15-3 Objectives
• Describe a conjugate acid, conjugate base, and amphoteric compound
• Explain the process of neutralization
• Explain how acid rain damages marble surfaces
Amphoteric
• A molecule or ion that can be classified as an acid or a base.
• Ex– HSO4
-
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Conjugate Acids & Bases
The species that remains after a Brønsted-Lowry acid has given up a proton is the conjugate base of that acid.
Example:
base
conjugate acid
(aq)OH aq)(F O(l)H HF(aq) 3-
2
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Conjugate Acids & Bases
The species that is formed when a Brønsted-Lowry base gains a proton is the conjugate acid of that base.
Example:
acid
conjugate base
(aq)OH aq)(F O(l)H HF(aq) 3-
2
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Brønsted-Lowry acid-base reactions are equilibrium systems (can occur both forward and reverse) and involve two acid-base pairs known as conjugate acid-base pairs.
acid base base acid
(aq)OH aq)(F O(l)H HF(aq)
2121
3-
2
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Strength of Conjugate Acids and Bases
The stronger the acid is the weaker its conjugate base
The stronger the base, the weaker its conjugate acid
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