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Lesson 14: Properties of Acids and Bases
Acids and Bases
Acids | Bases |
|---|---|
water soluble are electrolytes taste sourturn blue litmus redneutralize basesreact with metals to make H2(g)react with carbonates to make CO2(g) | water soluble are electrolytes taste bitterturn red litmus blueneutralize acidsfeel slippery |
Bases:
Arrhenius was the first scientist to propose a structure related to acids and bases.
He proposed that hydroxide ions (OH-) are responsible for the properties of bases. Ionic hydroxides (metal ion + OH- ion) are very common bases that separate into their ions when dissolved in water. This process of separation of ions is called dissociation.
Examples of Bases
sodium hydroxide - NaOH(aq)
NaOH(s) → Na+(aq) + OH-(aq)
calcium hydroxide – Ca(OH)2(aq)
Ca(OH)2(s) → Ca2+(aq) + 2 OH-(aq)
Acids
Arrhenius proposed that the H+ ion is responsible for the properties of acids. Acids are molecules with a hydrogen attached that can be released in water. This process of releasing the hydrogen ion is called ionization.
Ionization = the process in which a neutral molecule forms ions.
Examples: HCl(aq) 🡪 H+(aq) + Cl-(aq)
HC2H3O2 (aq) 🡪 H+(aq) + C2H3O2- (aq)
Strong and Weak Acids and Bases
Hydrochloric acid (HCl(aq)) and acetic acid (HC2H3O2(aq)) are both acids.
However, even if we take the same concentration of each acid, hydrochloric is much more corrosive than acetic acid and it conducts electricity better. It seems to have more acidic properties. Why is this?
Strong Acids
Hydrochloric acid is a strong acid. Strong acids are acids that ionize 100% in water.
HCl (aq) = H^1+ (aq) + Cl^1- (aq)
Less than half of the HC2H3O2 molecules ionize to make H1+ and C2H3O21-. Since H1+ ions are the ones that give an acid acidic properties, the end solution is less acidic than a strong acid.
Weak acids
Acetic acid is a weak acid. Weak acids are acids that ionize less than 50% in water.
HC2H3O2 (aq) = H^1+ (aq) + C2H3O2^1- (aq)
Less than half of the HC2H3O2 molecules ionize to make H1+ and C2H3O21-. Since H1+ ions are the ones that give an acid acidic properties, the end solution is less acidic than a strong acid.
Properties of Equal Concentrations of Strong and Weak Acids
Weak Acid | Strong Acid |
|---|---|
conducts electricity lessreacts more slowly with metalhigher pHless corrosive | conducts electricity morereacts more quickly with metallower pHmore corrosive |
Summary
Strong acids ionized 100% and are more “active”; Weak acids ionize less than 100% and are less “active”
OH- indicates bases; H+ indicate acids
Ionization - going from a neutral molecule to charged ions; dissociation - the “splitting apart” process
Lesson 14: Properties of Acids and Bases
Acids and Bases
Acids | Bases |
|---|---|
water soluble are electrolytes taste sourturn blue litmus redneutralize basesreact with metals to make H2(g)react with carbonates to make CO2(g) | water soluble are electrolytes taste bitterturn red litmus blueneutralize acidsfeel slippery |
Bases:
Arrhenius was the first scientist to propose a structure related to acids and bases.
He proposed that hydroxide ions (OH-) are responsible for the properties of bases. Ionic hydroxides (metal ion + OH- ion) are very common bases that separate into their ions when dissolved in water. This process of separation of ions is called dissociation.
Examples of Bases
sodium hydroxide - NaOH(aq)
NaOH(s) → Na+(aq) + OH-(aq)
calcium hydroxide – Ca(OH)2(aq)
Ca(OH)2(s) → Ca2+(aq) + 2 OH-(aq)
Acids
Arrhenius proposed that the H+ ion is responsible for the properties of acids. Acids are molecules with a hydrogen attached that can be released in water. This process of releasing the hydrogen ion is called ionization.
Ionization = the process in which a neutral molecule forms ions.
Examples: HCl(aq) 🡪 H+(aq) + Cl-(aq)
HC2H3O2 (aq) 🡪 H+(aq) + C2H3O2- (aq)
Strong and Weak Acids and Bases
Hydrochloric acid (HCl(aq)) and acetic acid (HC2H3O2(aq)) are both acids.
However, even if we take the same concentration of each acid, hydrochloric is much more corrosive than acetic acid and it conducts electricity better. It seems to have more acidic properties. Why is this?
Strong Acids
Hydrochloric acid is a strong acid. Strong acids are acids that ionize 100% in water.
HCl (aq) = H^1+ (aq) + Cl^1- (aq)
Less than half of the HC2H3O2 molecules ionize to make H1+ and C2H3O21-. Since H1+ ions are the ones that give an acid acidic properties, the end solution is less acidic than a strong acid.
Weak acids
Acetic acid is a weak acid. Weak acids are acids that ionize less than 50% in water.
HC2H3O2 (aq) = H^1+ (aq) + C2H3O2^1- (aq)
Less than half of the HC2H3O2 molecules ionize to make H1+ and C2H3O21-. Since H1+ ions are the ones that give an acid acidic properties, the end solution is less acidic than a strong acid.
Properties of Equal Concentrations of Strong and Weak Acids
Weak Acid | Strong Acid |
|---|---|
conducts electricity lessreacts more slowly with metalhigher pHless corrosive | conducts electricity morereacts more quickly with metallower pHmore corrosive |
Summary
Strong acids ionized 100% and are more “active”; Weak acids ionize less than 100% and are less “active”
OH- indicates bases; H+ indicate acids
Ionization - going from a neutral molecule to charged ions; dissociation - the “splitting apart” process
NoteStudied by 8762 peopleNoteStudied by 5 peopleNoteStudied by 30818 peopleNoteStudied by 6 peopleNoteStudied by 5 peopleNoteStudied by 4 people