Writing neutralization equations
When acids and bases are mixed, a salt forms
NaOH + HCl  H2O + NaCl
base + acid  water + salt
Ca(OH)2 + H2SO4  2H2O + CaSO4
Question: Write the chemical reaction when lithium
hydroxide is mixed with carbonic acid.
Step 1: write out the reactants
LiOH(aq) + H2CO3(aq) 
Step 2: determine products … H2O and Li2(CO3)
LiOH(aq) + H2CO3(aq)  Li2CO3(aq) + H2O(l)
Step 3: balance the equation
2LiOH(aq) + H2CO3(aq)  Li2CO3(aq) + 2H2O(l)
lithium hydroxide + carbonic acid  lithium carbonate + water
Assignment
Write balanced chemical equations for
these neutralization reactions. Under each
compound give the correct IUPAC name.
a)
b)
c)
d)
e)
f)
iron(II) hydroxide + phosphoric acid
Ba(OH)2(aq) + HCl(aq)
calcium hydroxide + nitric acid
Al(OH)3(aq) + H2SO4(aq)
ammonium hydroxide + hydrosulfuric acid
KOH(aq) + HClO2(aq)
a) 3Fe(OH)2(aq) + 2H3PO4(aq)  Fe3(PO4)2(aq) + 6H2O(l)
iron(II) hydroxide + phosphoric acid  iron (II) phosphate
b) Ba(OH)2(aq) + 2HCl(aq)  BaCl2 (aq) + 2H2O(l)
barium hydroxide + hydrochloric acid  barium chloride
c) Ca(OH)2(aq) + 2HNO3(aq)  Ca(NO3)2(aq) + 2H2O(l)
calcium hydroxide + nitric acid  calcium nitrate
d) 2Al(OH)3(aq) + 3H2SO4(aq)  Al2(SO4)3(aq) + 6H2O(l)
aluminum hydroxide + sulfuric acid  aluminum sulfate
e) 2NH4OH(aq) + H2S(aq)  (NH4)2S(aq) + 2H2O(l)
ammonium hydroxide+ hydrosulfuric acid ammonium sulfide
f) KOH(aq) + HClO2(aq)
 KClO2(aq) + H2O(l)
potassium hydroxide + chlorous acid  potassium chlorite
Calculations involving
Neutralization Reactions
Sample Problem 1
What volume of 0.250M sulfuric acid, H2SO4
(aq) is needed to react completely with 37.2 mL
of 0.650 M potassium hydroxide, KOH (aq)?
1. Step 1. Write a balanced equation for
the reaction.
H2SO4(aq) + 2KOH(aq)  2H20(l) + K2SO4 (aq)
H2SO4(aq) + 2KOH(aq)  2H20(l) + K2SO4 (aq)
Step 2. Using the information
provided, calculate the number of
moles of base.
c = .650 mol/L
V= 37.2 mL
= 0.0372 L
n = cV = (.65 mol/L)(0.0372L)
= 0.02418 mol
H2SO4(aq) + 2KOH(aq)  2H20(l) + K2SO4 (aq)
Step 3. Determine the number of moles
of H2SO4 needed to neutralize the
lithium hydroxide. (Use mole ratio, if
necessary)
=0.02418mol KOH X 1 mol H2SO4
2 mol KOH
=0.01209 mol H2SO4
H2SO4(aq) + 2KOH(aq)  2H20(l) + K2SO4 (aq)
Step 4. Find the volume of H2SO4(aq)
based on the moles and concentration
of H2SO4 solution.
c= n/V
V= n/c
= 0.01209 mol/0.250M
= 0.0484 L
= 48.4 mL
Problem 2: A 25.0 mL sample of hydrochloric acid
is titrated with 1.00 mol/L NaOH. The end point
is reached when 67.5 mL of base has been added.
Calculate the concentration of the acid in mol/L.
1. Step 1. Write a balanced equation for
the reaction.
HCl(aq) + NaOH(aq)  H20(l) + NaCl(aq)
HCl(aq) + NaOH(aq)  H20(l) + NaCl(aq)
Step 2. Using the information
provided, calculate the number of
moles of base.
c = 1.00 mol/L
V= 67.5 mL
= 0.0675 L
n = cV = (1.00 mol/L)(0.0675L)
= 0.0675 mol
HCl(aq) + NaOH(aq)  H20(l) + NaCl(aq)
Step 3. Determine the number of moles
of HCl needed to neutralize the
sodium hydroxide. (Use mole ratio, if
necessary)
In this case nA= nB = 0.0675 mol
HCl(aq) + NaOH(aq)  H20(l) + NaCl(aq)
Step 4. Find the concentration of
HCl(aq) based on the moles and
volume of HCl solution.
c= n/V
= 0.0675 mol/0.0250L
= 2.70 mol/L
Calculate the % of HCl (as m/m) in the
solution, given that its density is 1.100 g/mL
m=nM
=(2.70 mol)(36.36g/mol)
= 98.4 g
2.70 mol HCl
1.00 L of solution
% = 98.4g x 100
1100g
= 8.95%
m=DV
=(1.100g/mL)(1000mL)
= 1100 g
Titration
• Titrations are a chemical procedure involving the
addition of a solution of known concentration. The
objective is to determine the point in the reaction
when the moles of the known solution is equal to
the moles of the unknown solution.
• The concentration of the unknown solution can be
determined by:
• Concentrationunknown =Volumeknown x Concentrationknown
Volumeunknown
Titration Terminology
• Titrant-solution of known
concentration. It is added
slowly using a burette
• Sample-solution of
unknown concentration. It
is contained in a flask
• Primary
Standards/SolutionsSolution of know accurate
concentrations that are
used as titrants.
Titration Terminology
• Indicator-A solution that
changes color at the
equivalence point.
• Equivalence Point
(Stoichiometric Point)-the
amount of titrant required for
a complete reaction to occur.
(chemically equivalent
amounts have reacted).
• Endpoint-The point in a
titration where a measurable
change occurs (indicator
change, pH change)