applications of complexometric titration

1. NAME: M AAMIR RAZA
R.NO: 10
TOPIC: COMPLEXOMETRIC
TITRATION
SUBMITTED TO: MAM
AYESHA IMTIAZ

2. CONTENTS:
 INTRODUCTION
 COMPLEXOMETRIC TITRATION
 METAL-EDTA TITRATION
 EDTA-TITRATION CURVE
 METAL ION INDICATOR
 EDTA-TITRATION TECHNIQUE
 APPLICATION OF COMPLEXOMETRIC TITRATION
 MASKING AND DEMASKING AGENT
 EXAMPLE
 CONCLUSION

3. INTRODUCTION
 TITRATION: A technique in which solution of known conc.
Used To determine the concentration of unknown solution.
 CONDITIONS FOR TITRATION:
1. Reaction proceed rapidly.
2. Well defined stoichiometry.
3. Large equilibrium constant.

4. COMPLEXOMETRIC
TITRATION
 COMPLEX FORMATION TITRATION: A titration based on
formation of complex ion called complexometric titration.
 COMPLEX: Metal ion+ ligand
It may be electrically positive, negative or neutral. Metal ion are Lewis
acid and ligand are Lewis base.

5. COMPLEXOMETRIC
TITRATION
 LIGAND: Ligands are electron pair donor and form coordinated
covalent bond with metal ion.
 LIGANDS TYPES: One of the basis of number of donating
group Monodentate, Multidentate (Bidentate , Tridentate, Tetra
dentate …..)

6. METAL-EDTA TITRATION
 CONDITIONAL FORMATION CONSTANT Kf: It is also
called effective formation constant.
 CONTROL OF pH: The minimum pH is needed for titration of
many metal ions , provide a strategy for the selective Titration of one
ion in the presence of another.

7. METAL-EDTA TITRATION
 EDTA: EDTA is used as chelator ( hexadentate) . EDTA has six
potential sites for bonding a metal ion ;the four corbonyle groups and
two amino groups. EDTA is a hexaprotic system.
 FORMATION CONSTANT Kc: The equilibrium constant for
the reaction of metal with the ligand is called formation constant. Kc
also known as stability constant.

8. COMPLEXOMETRIC
TITRATION
 CHELATE: A chelate is produced when a metal ion coordinates with two
or more donor groups of a single ligand to form a five or six membered
heterocyclic ring.
 CHELATING AGENT: Multidentate ligand are chelating agents.
 CHELATE EFFECT: The multidentate ligand s form strong 1:1
complexes with many metal ions.
 STABILITY OF MULTIDENTATE COMPLEX: It mainly an
entropy effect. The reaction is favoured by negative enthalpy and positive entropy.

9. EDTA TITRAATION
TECHNIQUES
1. Direct Titration Method : It is simplest and the most convenient method in which the
standard solution of EDTA is slowly added to the metal ion solution till the end point is achieved.
2. Back Titration Method: In the method , an excess of standard as solution of EDTA is
added to the metal solution being determined so as to complex all the metal ions present in the solution.
The excess of EDTA left after the complex formation with the metal is back titrated with a standard
solution of a second metal ion .
3. Displacement titration : The metal to be analyzed is added to a metal –EDTA complex.
The analyte ion displaces EDTA from the metal and the metal is subsequently titration eth standard
EDDTA

10.  4 Indirect Titration: The anion is first precipitates with a metal
cation and the precipitate is washed and boiled with an excess of
disodium EDTA solution toform the metal complex

11. APPLICATION OF
COMPLLEXOMETRIC
TITRATION:
 Hardness of water: Actually , the hardness is due to both Ca and
Mg salts but the two are determined together in the titration. The
total Ca and Mg is titrated with standard EDTA solution using
eriochrome black –T as indicator.

12. MASKING AND
DEMASKING AGENTS:
 Masking Agent : is a reagents that protects some components
of the analyte from reaction with EDTA masking used to
prevent one element from interfering in the analysis of another
elements.
 Demasking agents: Is a reagent that release of a metal ion
from a masking agent.

13. EXAMPLE:
 Mg ion complex with EDTA:
 Mg2+ + In2- [ MgIn]

 [ MgIn] + H4 y [MgY]2- + 2H+

14. CONCLUSION :
 Complexometric titration is the volumetric titration through which
end point can be determined by different stabilities of metal –
indicator and metal – titration complex. Buffer solution resist the
changes pH. The selectivity afforded by masking , demasking and pH
control allows individual components of complex mixtures of metal
ions to be analyzed by EDTA titration