Arrhenius Acids & Bases

ACIDS
– Monoprotic (HNO3)
– Diprotic (H2SO4)
– Triprotic (H3PO4)
– Yield Hydrogen ions
(H+) in aqueous
solution

BASES
– Forms Hydroxide ions
(OH-) in aqueous
solution
BRONSTED – LOWERY
ACIDS

ACIDS
– Donates a
proton/hydrogen ion

BASES
– Accept
proton/hydrogen ion
Acids
Tart/sour taste
 Acid solutions are electrolytes (conduct
electricity)
 Cause indicators to change color
 High concentrations of hydrogen ions
 [H+]
 pH 0 – 6.9

Bases
Bitter taste
 Slippery feel
 Aqueous solutions are electrolytes
 Cause an indicator to change color
 High hydroxide ion concentration
 [OH-]
 pH 7.1 – 14.0

What ions do acids produce in greater concentrations in a solution?
What ions do bases produce in greater concentrations in a solution?
CONCENTRATED VS. DILUTE
STRONG ACIDS
HF
 HCl
 HBr
 HI
 HNO3
 H2SO4

“STRONG” indicates the degree of
dissociation!!!
NOT the degree of concentration!!!
WEAK ACIDS
Acids that DO NOT 100% dissociate
 REMINDERS:

– Acids of VERY high concentrations (greater
than 1M), will not 100% dissociate
– ALL acids have SOME concentration of
hydroxide ions….WHY??
STRONG BASES
GROUP
I HYDROXIDES
LiOH - lithium hydroxide
 NaOH - sodium hydroxide
 KOH - potassium hydroxide
 RbOH - rubidium hydroxide
 CsOH - cesium hydroxide

STRONG BASES
GROUP
II HYDROXIDES
*Ca(OH)2 - calcium hydroxide
 *Sr(OH)2 - strontium hydroxide
 *Ba(OH)2 - barium hydroxide


* These bases completely dissociate in solutions of 0.01 M or less.
The other bases make solutions of 1.0 M and are 100% dissociated
at that concentration. There are other strong bases than those
listed, but they are not often encountered.
WEAK BASES
Bases that DO NOT 100% completely
dissociate
 REMINDERS:

– Bases of VERY high concentrations (greater
than 1M), will not 100% dissociate
– ALL bases have SOME concentration of
hydrogen ions….WHY??
Ionization Constant
Example:
Ammonia in water
Ionization Constant
Example:
Ionization of nitric acid
Ionization Constants: Ka, Kb,
and Kw
http://www.saskschools.ca/curr_content/chem30_05/5_acids_bases/acids2_2.htm
• Ka
• Kb
• Kw
Ionization Constants: Ka, Kb,
and Kw

A large value of Ka
means there are many
H+ ions in solution in other words, a strong acid

A large Kb indicates
many OH- ions a strong base
Practice Set
Calculating pH/pOH
pH = -log [H+]
 pOH = -log [OH-]

pH + pOH = 14



[H+] = 10-pH
 [OH-] = 10-pOH
[H+] [OH-] = 1 x 10-14
Warm-Up
A 25.00 mL sample of a 0.5250 M
H2SO4 solution is titrated with a
NaOH solution using
phenolphthalein as the indicator. It
is found that 22.07 mL of the NaOH
solution is needed to reach the
endpoint of the titration. What is
the molarity of the NaOH solution?