This document describes different methods of argentometric titration: 1. Mohr's method uses silver nitrate solution and potassium chromate indicator to determine the content of chloride and bromide ions through a precipitation reaction. 2. Volhard's method uses thiocyanate ion as the titrant and ferric ion indicator to titrate excess silver ions from the initial reaction of silver nitrate with halide ions. 3. Fajans' method uses a pH indicator absorption method to determine the type of anion present based on the indicator used.

1. Argentometric Titration
AYESHA SHAFI

2. The Goal Determine the
number of titrant
needed to reach the
equivalence point of
the titration reaction
Argentometric is a process of
determining the content of a substance
based on precipitation reaction from
component of the test substance, using
precipitation formation of Ag+.

3. Mohr Methods
• The standard solution is silver nitrate solution using Potassium
Chromate indicator.
• Limited to a solution with a pH value of between 6 and 10.
• Use: determine the content of Chloride and Bromide.
Principle: Using Chromate indicator
NaCl + AgNO3  AgCl (precipitate) + NaNO3
2AgNO3 + K2CrO4 (precipitate) + 2KNO3

4. Mohr Methods
Titration should be done in neutral or semi-
alkalis atmosphere because:
1. In the acid precipitation atmosphere of AgCrO4 will
dissolve because the silver dichromate are formed
(Ag2Cr2O7)
2. In the silver nitrate base atmosphere will reacted
with hydroxide ion to form silver hydroxide
precipitation
AgNO3 + NaOH  AgOH (precipitation) + NaNO3

5. Mohr Methods
The disturbance of this titration:
1. Ion that will precipitate sooner than AgCl, example :
F, Br, CNS-
2. Ion that form complex with Ag+, example : CN-, NH3,
above pH 7
3. Ion that form complex with Cl-, example : Hg2+
4. Cation that precipitate the Chromate, example : Ba2+

6. Volhard Methods
• Indicator : Fe3+ (Ferry
Ammonium Nitrate) that
formed the Red color from
the iron (Fe) when it react
with SCN-.
• The materials that used:
• Standard solution Volume
of AgNO3
• Ion Halide (X-) example: Cl-
• Standard Solution
Thiocyanat (KSCN or
NH4SCN) as a titrant.
• Indicator iron (III) (Fe3+).
• The certainty:
• This titration are occur in
Acid condition with pH
under 3.
• If not, the end point can’t
be showed.

7. • Process:
Volhard Methods
leftover standard
solution of AgNO3
solution which
contains halogen
ion ,ex : (X-)
The excess of ion
Ag+ from AgNO3
which not react
with Halogen Ion
Will Experience
The titration
With Standard
solution of
thiocyanate (KSCN
or NH4SCN)
By using the
indicator of Iron
(III) (Fe3+).
Ag+ + Cl  AgCl(s) Ksp = 1.82 x 10-10
titrant #1 white precipitate
(excess)
Ag+ + SCN  AgSCN(s) Ksp = 1.1 x 10-12
titrant #2 white precipitate
Fe3+ + SCN  FeSCN2+ Kf = 1.4 x 10+2
indicator red precipitate

8. Fajans Methods
Indicator
pH
indicator of absorption
the type of anion and
the indicator used.

9. Differences in method