Strong acids
All (100%) of the H ionize to H+
HCL, H2SO4, HNO3 are all strong acids
Strong Bases
All (100%) of the OH ionize to (OH)-
NaOH and KOH are strong bases
WEAK acids and bases
Not all the hydrogen ions or hydroxide ions
come off (ionize) in solution
Carbonic acid and Phosphoric acids are
weak
Acid Base Reactions
Acids + Metals
In lab we did an experiment with Zinc and acid:
Zn(s) + HCl (aq)
H2(g) + ZnCl2 (aq)
Is this equation balanced? Balance it!
What type of reaction is it?
If we used copper instead of zinc, what would
happen? (hint: look at Table J)
Neutralization Reactions
Neutralization Reactions
Acid + Base
water + a salt
This is true for any acid and base
Because water (pH = 7= neutral) is
produced, the acid and the base are
neutralized
Write Neutralization Reactions
for…
Nitric acid + potassium hydroxide
Sulfuric acid + calcium hydroxide
Magnesium hydroxide and hydrochloric acid
Titration Equation
Remember: Molarity (M) = Moles/Liter
So….
moles = molarity x Liters
Titration Equation
In a neutralization reaction……
the number of moles of acid must be equal
to the number of moles of base
(or the end result will not be neutral! )
Titration Equation
Therefore, in a neutralization reaction….
Moles of Acid = Moles of Base
or
Moles (A)
=
Moles (B)
Titration Equation
Since we know that Moles = molarity x Liter,
We can substitute in for Moles
Moles of Acid
=
Moles of Base
Molarity(of acid) x liters(of acid) = Molarity(of base) x Liters
(of base)
Titration Equation
We simplify this equation: (see Table T)
Ma x Va =
Mb x Vb
Where Ma = molarity of acid
Va = volume of acid (in liters)
Mb = molarity of base
Vb = volume of base (in liters)
Ma x Va =
Mb x Vb
What is the concentration of HCl if 50 ml of a
0.25M KOH are needed to neutralize 20
ml of HCL solution?
Ma = ?
Va = 20 ml
Mb = .25M
Vb = 50 ml
Ma x .02L = .25M x .05L
Ma x Va =
Mb x Vb
What is the concentration of HCl if 50 ml of a
0.25M KOH are needed to neutralize 20
ml of HCL solution?
Ma x .02L = .25M x .05L
Ma = .25M x .05L
.02L
Ma = .625M
Titration
is used to very accurately
measure the volumes
of acids and bases
during a neutralization
reaction
Phenolphthalein indicator is clear in acids, pink in bases
Neutralization is reached
when the clear solution turns a
pale pink
If solution turns a dark pink, too much
base has been added and the solution
is now basic, not neutral
pH
pH
• pH
=7
• pH
0-6
Acidic
• pH
8-14
Basic
Neutral (pure water)
Indicators: Table M
• Change colors in the presence of acids or
bases
• Phenolphthalein = clear in acids, pink in
bases
• Litmus = red acid
Blue Base