1. GENERAL CHEMISTRY 1
ACID BASE REACTIONS

2. Class Objectives To outline the properties of acids and bases
To differentiate between Arrhenius and Bronsted- Lowry definitions for acids and bases
To explain neutralization reactions
To determine concentrations and dilutions of solutions

3. ACIDS Substance that ionize in aqueous solutions to for H+ ions.
They increase the conc of H+ ions in solution.
Properties
Sour taste
Change litmus from blue to red
They usually react with metals to yield H2 gas
Generally have H first in their chemical formula

4. Naming Acids Acids are named based on the anions they contain;
They usually end in –ic; or –ous
When the anion ends with –ide or –ate the acid end with –ic
When the anion ends with –ite the acid ends with –ous.
Formula Anion Name
HCl Chloride ion Hydrochloric acid
H2SO4 Sulfate ion Sulfuric acid
HNO2 Nitrite ion Nitrous acid
H2SO3 Sulfite ion Sulfurous acid

5. BASES Substances that accept (react with) H+ ions.
Produce hydroxide ions (OH−) in solution
Bases react with acids
Properties
Bitter taste
Slippery feel
Change litmus from red to blue

6. BASES Soluble hydroxide are alkalis e.g NaOH, KOH, Ca(OH)2, Ba(OH)2
NH3(aq) is a weak base
H2O(l) is a weak acid (or weak base)
H2O(l) ⇆ H+(aq) + OH−(aq)
When ammonia and water are mixed a proton is transferred e.g.
NH3 + H2O  NH4+ + OH−

7. MONOPROTIC ACIDS Can be Monoprotic, Diprotic, Triprotic
Yield one H+ ion per molecule of Acid
Examples HCl, HNO3, HC2H3O2
Diprotic Acids:
Yield two H+ ions per molecule of Acid
Example: H2SO4
Triprotic Acids:
Yield one 3H+ ions per molecule of Acid
Examples :H3PO4
Diprotic and triprotic Acids produce acid salts

8. Strong vs Weak Acids & Bases
Strong acids and bases are also strong electrolytes i.e almost 100% ionized
The solubility of compounds helps in identifying strong and weak electrolytes
Weak acids and bases are weak electrolytes i.e. few ions in solution
For strong acids the conc of H+ ions will be very high
Strong Acids HX (except HF), HClO3, HClO4,HNO3,H2SO4,
Strong Bases Group 1A and 2A, metal hydroxides ( except Be and Mg) – soluble hydroxides
Weak base: NH3

9. ACID-BASE REACTIONS Acid base reactions are proton transfer reactions
When an acid and a base are mixed in the correct stoichiometric proportions both acidic and basic properties disappear. The product is a salt.
The Anion of the salt comes from the acid
The cation of the salt comes from the base
Example:
HNO3 + KOH  KNO3 + H2O (HOH)

10. Acid Base Reactions Are Neutralization reactions
Acids and bases react as follows
Forming salt and water only (hydroxide)
HCl(aq)+ NaOH(aq)  NaCl(aq) + H2O(l)
Forming salt, water and gas ( carbonate, hydrogen carbonate)
HCl(aq)+ NaHCO3(aq)  NaCl(aq) + H2O(l) + CO2(g)
Forming salt and gas (sulfide)
HCl(aq)+ Na2S(aq)  NaCl(aq) + H2S(g)

11. CONCENTRATION
Concentration is the amount of solute dissolved in a given amount of solvent
Concentration can be expressed in several ways:
Volume percent
Weight percent
Weight/volume (mass/volume) percent
Molarity

12. Volume percent Volume percent
= volume of solute x volume of solution
Example:
rubbing alcohol is generally 70% by volume isopropyl alcohol. That means that 100 ml of solution contains 70 ml of isopropyl alcohol.

13. Weight/volume percent
=   weight of solute (in g) x 100 volume of solution (in mL)
An example would be a 5%(w/v) NaCl solution. It contains 5 g of NaCl for every 100 mL of solution.

14. Weight Percent Weight percent
= weight of solute x weight of solution
To get weight percent we need the weight of the solute and the total weight of the solution.

15. MOLARITY Molarity (M) – Molar concentration
The concentration of a solution expressed as moles of solute per liter of solution
Molarity = moles solute
volume of solution in liters

16. DILUTION
The process of preparing a less concentrated solution from a more concentrated one
Moles solute before dilution = Moles solute after dilution
MCVC = MDVD

17. TITRATIONS
The process of reacting a solution of unknown concentration with one of known concentration.
Standard solution: solution of known concentration

18. TITRATIONS Can be used in the following reactions: Acid-Base
Precipitation
Oxidation-Reduction.

19. Homework Textbook Chapter 4 Section: 4.3; 4.5 & 4.6
End of chapter questions 4.27 – 4.43