Acids, Bases, and Salts

1
Acids, Bases, and Salts
2
I. Properties of Acids

• Sour taste
• Change colors of acid-base indicators warm
  colors turns litmus paper red
• Some react with active metals to release H2
• Acid Base ? Salt water
• Conduct electric current

3
III. Properties of Bases

• Bitter taste
• Change colors of acid-base indicators cool
  colors turns litmus paper blue
• Feel slippery
• React with acids to produce salts and water
• Conduct electric current

4
Write dissociation equation balance

• HCl ?
• HNO3 ?
• NaOH ?
• Mg(OH)2 ?
• NaCl ?
• Note any similarities between the equations

5
IV. ARRHENIUS THEORY

• Acids, bases, and salts conduct a current when
  dissolved in water - electrolytes
• An acid produces H in a water solution
  HCl(g) --gt H(aq) Cl-(aq)
• A base produces OH- in a water solution NaOH(cr)
  --gt Na(aq) OH-(aq)

6
II. Naming Acids - Binary

• Binary acid contains 2 elements hydrogen and
  one of the more electronegative elements.
• Ex. HF
• 1. Begins with prefix hydro
• 2. Followed by root of name of second element
• 3. Ends with suffix -ic
• hydro fluor ic acid
• H2S

7
II. Naming Acids - oxyacids

• Compound of hydrogen, oxygen, and a 3rd element
  that is usually a nonmetal
• Formula is usually one or more H atoms followed
  by polyatomic anion
• Pg. 250
• HNO2 nitrous acid NO2- nitrite
• HNO3 nitric acid NO3- nitrate
• Common industrial sulfuric, nitric, phosphoric,
  hydrochloric, acetic

8
Practice problems

• Pg.250 s 18-22
• Pg. 596 1a,1b

9
Strong vs. weak

• Strong acids and bases fully dissociate
• Weak acids and bases partially dissociate

10
V. BRONSTED-LOWRY THEORY

• Acid proton (H) donor Base proton acceptor
• The conjugate base of an acid is the particle
  that remains after a proton is released by the
  acid.
• The conjugate acid of a base is formed when the
  base receives a proton from an acid.
• In the reaction NH3(g) water(l)-gtNH4 (aq)
  OH- NH3 is the base, water is the acid, NH4 is
  the conjugate acid, and OH- is the conjugate base.

N
H
H
N
O
O
H
H
H
H
H
H
H
H
11
PRACTICE PROBLEMS

• Which is the conjugate base / conjugate acid in
• H3PO4 H2O --gt H3O H2PO4-
• H3O is the conjugate acid and H2PO4 is the
  conjugate base.
• One more, which is the conjugate base / conjugate
  acid in
• H4P2O7 H2O --gt H3O H3P2O7-
• Again H3O is the conjugate acid and H3P2O7- is
  the conjugate base.

12
BRONSTED-LOWRY Acid Base Reactions

• HF H2O ? F- H3O
• Subscripts designate 2 conjugate acid base pairs
• HF H2O ? F- H3O
• acid1 base2 base1 acid2
• Strength of conjugate acid and base strong acid
  weak conj. Base. Reactions favors direction
  that produces weaker acids and bases

13
Amphoteric

• Can act as acid or base (H2O)
• H2SO4 H2O ?
• base
• NH3 H2O ?
• acid

14
BRONSTED-LOWRY THEORY

• Monoprotic acid donates only one proton
• Polyprotic acid donates more than one proton
• Diprotic donates 2 protons
• Triprotic donates 3 protons
• All polyprotic ionize in steps
• H3PO4(aq) pg. 601 3a,3b

15
LEWIS THEORY

• Lewis focused on an electron transfer rather than
  a proton transfer.
• Lewis described an acid as an electron-pair
  acceptor and a base as an electron-pair donor.
• An acid or base in Arrhenius theory is the same
  under the Lewis and Bronsted-Lowry theories.

16
MORE PRACTICE PROBLEMS

• CLASSIFY THE FOLLOWING SUBSTANCES AS LEWIS ACIDS
  OR BASES.
• a. Cl- b. Al c. Br- d. I
• a and c Lewis Base
• b and d Lewis Acid