1. Unit 12: Acids, Bases, and Salts

2. Properties of Acids Taste sour
Electrolytes: substances that produce ions in solution and as a result conduct electricity
Strong acid  strong electrolyte
Weak acid  weak electrolyte
Will react with active metals (above H2 on Table J) to produce H2(g)

3. Review of Naming Rules Binary Acids: hydro_______ic acid
Ternary Acids (use Table E)
ate ic
ite ous

4. Properties of Bases Taste bitter Turn litmus paper blue
Feel slippery (ex. soap)
Strong bases consist of a Group 1 or Group 2 metal w/ hydroxide ion

5. Look in RT for common acids and bases

6. Electrolytes Form ions in water Conduct electricity
Salts
Ionic Compounds
M to NM
Acids
pH < 7
H+ > OH-
Bases
pH > 7
OH- > H+
Molecules (NM to NM) are NOT electrolytes…do NOT produce ions in solution!!

7. Indicators- Table M Below the range  the color is given on the left
Above the range  the color is given on the right.
Acids: Turn litmus red and phth colorless
Bases: Turn litmus blue and phth pink.

8. Universal Indicator

9. Arrhenius Theory of Acids and Bases
Arrhenius Acid
Arrhenius Base
A substance, that when dissolved in water, produces H+ ions as the only positive ions in solution
A substance, that when dissolved in water, produces OH- ions as the only negative ions in solution
Monoprotic, diprotic, triprotic
Hydronium ion
HCl (aq)  H+ (aq)+ Cl- (aq)
NaOH (aq)  Na+ (aq) + OH- (aq)
hydrogen ion, same as H3O+ (hydronium ion)
hydroxide ion

10. Bronsted-Lowry Theory of Acids and Bases ***based on the proton (H+)
Bronsted Acid
Bronsted Base
A proton donor
A proton acceptor
Must release the H+ (aq) ion
Does not need to have the OH-(aq) ion, but MUST have a lone pair of electrons.
Ex) HCl (aq)
Ex) NH3 (aq)

11. Reversible Acid-Base Rxns
Acid-Base reactions can be reversible! H2SO4(aq) + NH3(aq) HSO4-(aq) + NH4+(aq) B.A. B.B. B.B. B.A.
A conjugate acid-base pair consists of two substances related by the loss or gain of a single hydrogen ion (H+)
Pg.9

12. Amphoteric Substances
A substance that can act as both an acid and a base is said to be amphoteric
Ex) HCO3- (aq) + H2O (l)  CO32- (aq) + H3O+(aq)
**Here, HCO3- acts as an acid
Ex) HCO3- (aq) + H2O (l)  H2CO3 (aq) + OH- (aq)
**Here, HCO3- acts as a base
Water is a common amphoteric substance- can act as both an acid and base

13. Water as an Acid/Base Water molecules undergo self-ionization
H2O(l) + H2O (l) H3O+ (aq) + OH- (aq)
In pure water, the equilibrium concentration of [H3O+] = [OH-] = 1 x 10-7 M
In other words, a neutral solution has the same number of moles of H+ ions as OH- ions.

14. “See-Saw Diagram”
Ion-Product Constant for Water (for aqueous solutions) Kw= [H+] x [OH-] = 1.0 x 10-14
** exponents always add to 14

15. The pH scale
Scale is based on the concentration of H+ ions in aqueous solution
pH = - log [H+]
pH < 7, acidic
pH = 7, neutral
pH > 7, basic

16. Determining pH given concentrations
[H+] = 1.0 x 10-6 M
pH = 6
pH + pOH ALWAYS equals 14
[OH-] = 1.0 x 10-8 M
pOH = 8

17. The pH scale is logarithmic
An increase in one unit of the pH scale represents a ten-fold decrease (x 10) in the H+ ion concentration

18. Practice pH 6 to pH 4 pH 5 to pH 6 [H+] increases by a factor of 100
[H+] decreases by a factor of 10
pH 2 to pH 4
[H+] decreases by factor of 100

19. Neutralization Reactions
Neutralization occurs when an acid and a base react to form a salt and water
Acid + Base  salt + water
HCl (aq) + NaOH (aq)  NaCl (aq) + H2O (l)
Acid Base Salt Water

20. Titrations
Used to determine the concentration of an acid or base
The equivalence point is reached when the moles H+ = moles OH-
Titration Equation:
MaVa = MbVb
** Can use any unit of volume as long as you are consistent

21. unknown volume, known concentration
Known volume, unknown concentration

22. Warm-Up
In the lab, a student neutralized 1.5 M nitric acid with 0.50 M magnesium hydroxide.
Write the balanced equation for the rxn between the acid and base given above.
How many mL of 0.50 magnesium hydroxide are needed to neutralize 10.0 mL of 1.5 M nitric acid?

23. Indicators for Titrations
Phenolphthalein is used to approximate the endpoint of a titration.
Colorless indicates an acidic solution and pink indicates a basic solution
When a pale pink color persists, the endpoint has been reached
The endpoint, or equivalence point, is when moles H+ = moles OH- (pH =7)

24. Indicators- Table M Below the range  the color is given on the left
Above the range  the color is given on the right.

25. Strength of Acids/Bases
Strong Acids: Strong Bases:
HCl
HBr HI
HClO4
H2SO4
HNO3
Any Group 1 or 2 metal bonded to an OH- ion
Consider everything else to be weak!

26. Chemistry of Dyeing Eggs
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