1. Acids and Bases
Chapter 14

3. Properties of Acids and Bases
Aqueous solutions of acids have a sour taste.
Aqueous solutions of bases taste bitter.
Acids turn blue litmus paper red.
Bases turn red litmus paper blue.
Some acids react with metals to produce hydrogen gas.
Dilute aqueous solutions of bases feel slippery.
Acids react with bases to produce salts and water.
Bases react with acids to produce salts and water.
Acids conduct electric current.
Bases conduct electric current.
pH =
pH =

4. Naming Acids Hydrochloric Acid Hydrobromic Acid Hydrocyanic Acid
Binary Acids
A binary acid contains hydrogen and one other element
To name a binary acid:
The first word begins with the prefix hydro- and the root of the second element plus the suffix –ic
The second word is always acid
Example: HCl: HBr:
Although the term binary means two elements, a few acids with more than two elements follow the same naming rules as a binary acid. If no oxygen is present in the formula, the rule is the same except the root of the polyatomic ion that the acid contains is used.
Example:
HCN:
Hydrochloric Acid
Hydrobromic Acid
Hydrocyanic Acid

5. Naming Acids Continued
Oxyacids:
An acid that contains both a hydrogen atom and an oxyanion (a polyatomic ion containing one or more oxygen atoms) is referred to as an oxyacid.
To name an oxyacid:
Identify the polyatomic ion present.
The first word of an oxyacid’s name consists of the root of the oxyanion and the prefix “per-“ or “hypo” if that is part of the name.
Add a suffix: follow the chart if the polyatomic has the following ending
The second word is always acid.
Example:
HNO3: HNO2:
Ending
Acid Suffix
ate-
-ic
ite-
-ous
Nitric Acid
Nitrous Acid

6. Strengths of Acids/Bases
Strong Acid
An acid that nearly completely ionizes in a solution.
Is a strong electrolyte.
Acid strength increases with increasing polarity and decreasing bond energy.
A strong acid essentially ionizes 100%.
Examples:
Weak Acid
An acid that only slightly dissociates in a water solution, which contains H3O+ ions, anions, and dissolved acid molecules.
Only a small percent of acid molecules donate their hydrogen, and most remain the same.
Weak electrolyte.
HCl, HNO3, HClO4
HC2H3O2 and HCN

7. Strengths of Acids/Bases continued
Strong Base
A base that dissociates almost completely into its ions.
Strong electrolyte.
All oxides and hydroxides of group 1 and 2 are strong bases.
A strong base dissociates 100%.
Examples:
**** When a base completely dissociates in water to yield OH- ions, the solution is called alkaline.
Weak Base
Most bases are weak.
They dissociate only slightly in a water solution.
Weak electrolyte.
A weak base ionizes to a small extent.
Example:
NaOH, Ca(OH)2
NH3

8. General Rule for strong or weak acid/base
Strong binary acids:
Only HCl, HBr, HI, all other binary acids are weak.
Strong oxyacids:
Ratio of O to H is 2 or greater
For example: H2SO4 or HNO3
Strong bases:
Hydroxides of groups 1 and 2 (except Be), all others are weak.

9. How to determine between a strong acid and weak acid in Lab
Use a conductivity apparatus test (light bulb will be brighter for a strong acid).
Measure conductivity of solutions (strong acid will have a higher conductivity).
React the two acids with a metal like magnesium (stronger acid will react faster, more bubbling as H2 is formed)
Measure the pH of the solutions using a pH meter or indicators (strong acid has a lower pH)

10. How to determine between a strong base and weak base in Lab
Use a conductivity apparatus test (light bulb will be brighter for a strong base)
Measure conductivity of solutions (strong base will have a higher conductivity)
React the two bases with a chemical and observe the rate of the reaction (stronger base will react faster)
Measure the pH of the solutions using a pH meter or indicators (stronger base has a higher pH)

11. Hydroxide and hydronium ions
All water solutions contain H+ and OH- ions.
An acidic solution contains more H+ than OH-, neutral solution contains equal amounts of both. (water)
Water self ionizes to form hydronium ions and hydroxide ions (H2O + H2O  H3O+ + OH-)
Hydronium ion is a hydrogen ion covalently bonded to a water molecule – more stable

12. Industrial uses for acids
Sulfuric Acid
Most commonly produced industrial chemical in world
Used in petroleum refining & making fertilizer
Used in production of metals, paper, paint, detergents, car batteries
Used to remove water
Nitric Acid
Used to make explosives, rubber, plastic, dyes, and pharmaceuticals
Phosphoric Acid
Used to make fertilizers, animal feed, and detergents, flavoring agent in beverages, cleaning agent
Hydrochloric Acid
Used as pickling agent for iron and steel (removes surface impurities), cleaning agent in industry, food processing, activation of oil wells, maintaining correct acidity of swimming pools
Acetic Acid
Used to make plastic and food supplements

13. Types of Acid/Base Models
Arrhenius
-A substance that contains hydrogen and ionizes to produce hydrogen ions in aqueous solution
- H+ producer
- Example: HCl (g) → H+ (aq) + Cl- (aq)
- A substance that contains a hydroxide group and dissociates to produce a hydroxide ion in aqueous solution.
- OH- producer
- Example: NaOH (g) → Na+ (aq) + OH- (aq)
Bronsted-Lowry
- An acid is a hydrogen ion donor when dissolved in water.
- H+ donor
- A base is a hydrogen ion acceptor when dissolved in water.
- H+ acceptor
Lewis
- An acid is an electron-pair acceptor
- Can accept (share) an electron pair
- A base is an electron pair donor
- Has a lone electron pair that it can donate

14. Conjugate Acids and Bases
In the Bronsted-Lowry Model, acids donate a hydrogen ion to a water molecule. The water acts as a base by accepting the hydrogen ion forming the hydronium ion.
Example: HCl (aq) + H2O (l) ↔ H3O+ (aq) Cl- (aq)
The forward reaction is the reaction of an acid and a base. The reverse is also the reaction of an acid and a base; however the acid and base are identified as the conjugate acid and the conjugate base.
Conjugate Acid – the species produced when a base accepts a hydrogen ion.
Conjugate Base – The species that results when an acid donates (or loses) a hydrogen ion.
Example: HCl (aq) H2O (l) ↔ H3O+ (aq) Cl- (aq)
A conjugate acid-base pair consists of two substances related to each other by donating and accepting a single hydrogen ion.
Amphoteric – can act as both an acid and a base
Example:
Acid
Base
Acid
Base
Conjugate Acid
Conjugate base
Water

15. Common acids and their conjugate base (more listed on page 467)
HCl
Cl-
HNO3
NO3-
H2SO4
HSO4-
HC2H3O2
C2H3O2-
H3PO4
H2PO4-

16. Practice:
Identify the conjugate acid base pairs in each of the following:
HF (aq) + H2O (l) ↔
NH3 (aq) + H2O (l) ↔
As you can see from the above reactions, water can act as either an acid or a base…. Which makes it: _________________________
For each of the following acids or bases give the conjugate formed:
H3PO ____________________
NH ____________________
F ____________________
HCN ____________________
H3O+ + F-
Acid
Base
Conjugate Acid
Conjugate base
NH4+ + OH-
Base
Acid
Conjugate Acid
Conjugate base
Amphoteric
H2PO4 -1
NH4 +1 HF
CN -1

17. Classification of Acids
Acids are classified as either monoprotic or polyprotic.
Mono – meaning having “one” hydrogen ion to donate
Poly – meaning having “more than one” hydrogen ions to donate
Diprotic – having two hydrogen ions to donate
Triprotic – having three hydrogen ions to donate
Looking at the chemical formula for an acid, one can distinguish whether the acid is monoprotic or polyprotic

18. Examples:
Identify whether each of the following are monoprotic, diprotic, or triprotic acids.
HCl ___________________
HC2H3O ___________________
H3PO ___________________
H2CO ___________________
Mono
Mono
Tri Di

19. Neutralization Reactions
A neutralization reaction is a reaction in which an acid and a base in an aqueous solution react to produce a salt and water.
Salt- ionic compounds made up of a cation (+ ion) from a base and an anion (- ion) from an acid
Neutralization Reactions are double replacement reactions
AB CD → CB H2O
Acid
Base
Salt
Water

20. Examples:
Give the neutralization reaction for each of the following and name the salt produced in the reaction:
Magnesium hydroxide + hydrochloric acid →
Hydrochloric acid + sodium hydroxide →
Sulfuric acid + calcium hydroxide → 2 → 2
___ Mg(OH)2 + ___ HCl
___ MgCl2 + ___ H2O
___ HCl + ___ NaOH →
___ NaCl + ___ H2O
___ H2SO4 + ___ Ca(OH)2 →
___ CaSO4 + ___ H2O 2