Transcript Acid/Base powerpoint

Acids and Bases
A. Acids
1. Aqueous solutions of acids have a sour taste.
Don’t do this!!
2. Acids change the color of acid-base indicators.
3. Some acids react with active meals to release H2 gas.
4. Acids react with bases to produce salts and water.
5. Some acids conduct electric current.
6. Two types of acids:
a. Binary acids
i. Contain only two different elements:
H and one of the more EN elements.
ii. Hydro-X-ic acid, See Table 1 on page 468.
b.Oxyacids
i.Compound of H, O, and a third element, usually a
nonmetal.
ii.Name depends on anion that is present.
Some Common Industrial Acids
1. Sulfuric Acid
a. Most commonly produced.
b.Used in production of metals, paper, paint, dyes,
detergents, automobile batteries, dehydration agent.
2. Nitric Acid
a. Volatile and unstable when pure.
b.Used in explosives, rubber, plastics, dyes, and
pharmaceuticals
3. Phosphoric acid
a. When dilute, it is nontoxic.
b.Used in fertilizers, animal feed, detergents, ceramics.
4. Hydrochloric Acid
a. Acid that is produced by stomach.
b.Used as a cleaning agent, in food processing,
production of other chemicals.
5. Acetic Acid
a. Clear, colorless, pungent-smelling.
b.Vinegar is 4-8% acetic acid.
c. Used in synthesizing chemicals, plastics, and as a
fungicide.
C. Bases
1. Aqueous solutions of bases taste bitter.
2. Bases change the color of acid base indicators.
3. Dilute aqueous solutions of bases feel slippery. (like
soap)
4. Bases react with acids to produce salts and water.
5. Bases conduct electricity.
D. D. Arrhenius Acids and Bases
1. Developed by Svante Arrhenius.
2. An Arrhenius acid is a chemical compound that
increases the concentration of H+ ions in aqueous solution.
Acids will ionize in solution increasing that number of H+
ions present.
3. An Arrhenius base is a substance that increases the
concentration of hydroxide ions (OH-) in aqueous solution.
Some are ionic hydroxides, some react with water to
produce hydroxides.
4. Strength of Acids
a. A strong acid is one that ionizes completely in aqueous
solution. Strong acids are strong electrolytes. (Ex. HCl)
b. A weak acid is one that does not ionize completely.
They are weak electrolytes. (Ex. CH3COOH)
c. Strong acids are assumed to ionize completely.
Number of H’s present does not indicate strength of acid.
d.Organic acids (-COOH) are generally weak.
5. When a base completely dissociates in water to yield
aqueous OH- ions the solution is said to be alkaline.
- Not all bases are ionic (NH3).
6. Strength of Bases
a. Strong bases dissociate completely, and are strong
electrolytes. Ex. NaOH
b. Weak bases do not dissociate completely, and are
weak electrolytes. Ex. NH3
II.Acid-Base Theories
A. Arrhenius Definition:
We’ve already discussed it.
B.B. Brnsted-Lowry Acids and Bases
1. Brnsted-Lowry acids are molecules or ions that are
proton donors.
2.Brnsted-Lowry bases are molecules or ions that are
proton acceptors.
3.In a B-L reaction, a proton is transferred from one (acid)
to another (base). Looking at the reaction will tell
which is which.
4. Monoprotic acids can only donate one proton per molecule.
5. Polyprotic acids can donate multiple protons per
molecule.
a. Diprotic acids can donate two protons per molecule.
b.Triprotic acids can donate three protons per
molecule.
6. For example: HCl and water.
C. C. Lewis Acids and Bases
1. A Lewis acid is an atom, ion, or molecule that accepts an
electron pair to form a covalent bond.
2. A Lewis base is an atom, ion, or molecule that donates an
electron pair to form a covalent bond.
3. A Lewis acid-base reaction is the formation of one or
more covalent bonds between an electron-pair donor and
an electron-pair acceptor.
4. For example: BF3 and NH3.
III. Acid-Base Reactions
A. Conjugate Acids and Bases
1. A conjugate base is the species that remains after a B-L
acid has given up a proton.
2. A conjugate acid is the species that remains after a B-L
base has accepted a proton.
3. Generally, strong acids have weak conjugate bases, and
strong bases have weak conjugate acids.
B.Amphoteric Compounds
1. An amphoteric compound can act as either an acid or as
a base. For example water.
2. -OH (hydroxyl) groups in molecules can be acidic or
basic. This is due to the polarity of the group.
C. C.
Neutralization Reactions
1. A neutralization reaction occurs when an acid and a base
react.
2. The neutralization is the reaction of hydronium and
hydroxide ions to form water molecules. Another
product of these reactions is a salt, and ionic substance.
3. For example, NaOH and HCl.
4. Acid rain
a. Occurs as a result of many industrial processes. These
processes produce gases such as NO, NO2, CO2, SO2,
and SO3.
b.These gases dissolve in water to form acids. This acid
then falls as acid rain.
c. Acid rain causes many harmful effects. pH problems,
erosion, and others.