3. An indicator is
usually some weak
organic acid or base
dye that changes
colors at definite
pH values.
4. The weak acid form
(Hin) will have one
color and the
negative ion (In-)
will have different
colors.
5. Indicator Color (Acid) Color (Base)
Thymol Blue-
1st Change
Red Yellow
Methyl Orange Red Yellow
Bromoscresol
Green
Yellow Blue
Methyl Red Yellow Red
15. When the spectator ions are removed,
the net ionic equation shows
the H+H+ and OH−OH− ions forming
water in a strong acid, strong base
reaction:
H+(aq)+OH−(aq)⇋H2O(l)H(aq)++OH(
aq)−⇋H2O(l)
16. When a strong acid
neutralizes a strong
base, the pH of the
salt solution will
always be 7.
17. Weak Acid-Weak Base Neutralization
A weak acid, weak base reaction can
be shown by the net ionic equation
example:
H+(aq)+NH3(aq)⇋NH+4(aq)H(aq)
++NH3(aq)⇋NH4(aq)+
18. When a strong acid
neutralizes a weak
base, the resulting
solution's pH will
be less than 7.
19. When a strong base
neutralizes a weak
acid, the resulting
solution's pH will
be greater than 7
20. Strength of Acid and Base pH Level
Strong Acid-Strong Base 7
Strong Acid-Weak Base <7
Weak Acid-Strong Base >7
Weak Acid-Weak Base pH <7 if Ka>KbKa>Kb
pH =7 if Ka=KbKa=Kb
pH >7 if Ka<KbKa<Kb