1. Acids and Bases

2. Take notes on your own paper today…
Write down things that are in yellow You’ll need this information to answer the lab questions

3. Svante Arrhenius
He was a Swedish chemist ( ), and a Nobel prize winner in chemistry (1903)
one of the first chemists to explain the chemical theory of the behavior of acids and bases
Dr. Hubert Alyea (professor emeritus at Princeton University) was the last graduate student of Arrhenius.

4. Hubert N. Alyea ( )

5. 1. Arrhenius Definition - 1887
Acids produce hydrogen ions (H1+) in aqueous solution (HCl → H1+ + Cl1-)
Bases produce hydroxide ions (OH1-) when dissolved in water.
(NaOH → Na1+ + OH1-)

6. Svante Arrhenius ( )

7. 2. Brønsted-Lowry – 1923
A broader definition than Arrhenius
Acid is hydrogen-ion donor (H+ or proton); base is hydrogen-ion acceptor.
Acids and bases always come in pairs.
HCl is an acid.
When it dissolves in water, it gives it’s proton to water.
HCl(g) + H2O(l) ↔ H3O+(aq) + Cl-(aq)
Water is a base; makes hydronium ion.

8. Johannes Brønsted Thomas Lowry (1879-1947) (1874-1936) Denmark England

9. Properties of Acids Acids taste sour Acids have a pH lower than 7
Acids effect indicators
Blue litmus turns red
Universal indicator turns red
Acids are proton (hydrogen ion, H+) donors
Acids react with active metals, produce H2
Acids react with carbonates
Acids neutralize bases

10. Acids Effect Indicators
Blue litmus paper turns red in contact with an acid.

11. Acids Have a pH less than 7

12. Acids React with Active Metals
Acids react with active metals to form salts and hydrogen gas.
Mg + 2HCl  MgCl2 + H2(g)

13. Acids Neutralize Bases
HCl + NaOH  NaCl + H2O
Neutralization reactions ALWAYS produce a salt and water.

14. Sulfuric Acid Used in the production of paper
Highest volume production of any chemical in the U.S.
Used in the production of paper
Used in production of fertilizers
Used in petroleum refining

15. Nitric Acid Used in the production of fertilizers
Used in the production of explosives
Nitric acid is a volatile acid – its reactive components evaporate easily
Stains proteins (including skin!)

16. Hydrochloric Acid Used in the pickling of steel
Used to purify magnesium from sea water
Part of gastric juice, it aids in the digestion of protein
Sold commercially as “Muriatic acid”

17. Phosphoric Acid A flavoring agent in sodas
Used in the manufacture of detergents
Used in the manufacture of fertilizers
Not a common laboratory reagent

18. Acetic Acid Used in the manufacture of plastics
Used in making pharmaceuticals
Acetic acid is the acid present in vinegar

19. Organic Acids
Organic acids all contain the “carboxyl” group, sometimes several of them.
The carboxyl group is a poor proton donor, so ALL organic acids are weak acids.

20. Examples of Organic Acids
Citric acid in citrus fruit
Malic acid in sour apples
Deoxyribonucleic acid, DNA
Amino acids, the building blocks of protein
Lactic acid in sour milk and sore muscles
Butyric acid in rancid butter

21. Acids are Proton Donors
Monoprotic acids
Diprotic acids
Triprotic acids
HCl
H2SO4
H3PO4
HC2H3O2
H2CO3
HNO3

22. Ionization of HCl and formation of hydronium ion, H3O+
H2O + HCl 
H3O+ + Cl-
Proton
acceptor
Proton
donor

23. Strong Acids vs. Weak Acids
Strong acids are assumed to be 100% ionized in solution (good proton donors).
HCl
H2SO4
HNO3
Weak acids are usually less than 5% ionized in solution (poor proton donors).
H3PO4
HC2H3O2
Organic acids

24. Effects of acid on the Environment
Rainwater is naturally acidic WHY? When CO2 (gas) + H2O H2CO3 (aqueous) react they form Carbonic acid Carbon dioxide (from the air) dissolves in rainwater, producing carbonic acid, a weak acid The normal pH of rainwater is about 5.6

25. Effects of acid on the Environment
Acid rain is rain with a pH less than 5.
Forms when air-polluting gases dissolve in
Rainwater
Sulfur dioxide (SO2) Further lowers the pH of rain.

26. Effects of acid on the Environment
Environmental Impact of Acid Rain
Dependent on local geology
Hill Country soil is rich in limestone (CaCO3), which is basic
Limestone neutralizes the effect of acid rain on lakes

27. Damages Caused by Acid Rain 1) Damage to aquatic life
In some sensitive lakes and streams, acidification has completely eradicated
fish species, such as the brook trout, leaving these bodies of water barren. Hundreds of the lakes in the Adirondacks have acidity levels unsuitable for the survival of fish

28. Damages Caused by Acid Rain (Cont.) 2.) Damage to vegetation

29. Damages Caused by Acid Rain (Cont
Damages Caused by Acid Rain (Cont.) 3) Damage to outdoor artwork (monuments & statues)

30. Properties of Bases Bases taste bitter Bases have a pH greater than 7
Bases effect indicators
Red litmus turns blue
Universal indicator turns blue
Phenolphthalein turns purple
Bases are proton (H+) acceptors
and usually have hydroxide ions- OH-
Solutions of bases feel slippery
Bases neutralize acids

31. Examples of Bases Sodium hydroxide (lye), NaOH
Potassium hydroxide, KOH
Magnesium hydroxide, Mg(OH)2
Calcium hydroxide (lime), Ca(OH)2

32. Bases Effect Indicators
Red litmus paper turns blue in contact with a base.
Phenolphthalein turns purple in a base.

33. Bases have a pH greater than 7

34. Bases Neutralize Acids
Milk of Magnesia contains magnesium hydroxide, Mg(OH)2, which neutralizes stomach acid, HCl.
2 HCl + Mg(OH)2
MgCl2 + 2 H2O

35. Products of Neutralization
HCl + NaOH 
NaCl + H2O
H2SO4 + Ca(OH)2 
CaSO H2O
HNO3 + KOH 
KNO3 + H2O
The products of neutralization are always a ______ and _______.
salt
water