4. PRINCIPLES OF
TITRIMETRIC
ANALYSIS
INTRODUCTION:
Volumetric Analysis: Deals with the measurement of volume of solutions
involved in chemical reactions which ultimately lead to the
determination of the amount of constituents of substance
.
Pharmaceutical Analysis: it is the quantitative measurement of
the active ingredient and related compounds in the
pharmaceutical product
Manufacturing control:
Determination of drugs and their metabolites in biological samples,
generally plasma is important in elucidation of drug metabolism
pathways as well as comparing bio availabilityb of different formulae.
5. TITRATION
The process in which concentration of unknown solution is
determined with the help of standard solution by using the
indicator is called Titration
TITRANT:
The solution of known concentration which is usually taken in
a burette is called Titrant
Titrand:
The solution of unknown concentration which is being titrated
and ususally taken in a conical flask is called Titrand
End Point:
The point in a titration at which reaction between two solution
is just completed and at which indicator can show sharp
colour change is called end point
6. NORMALITYFACTOR:
It is defined as the ratio of
actual weight of the
substance taken to the
theoretical weight of the
substance to be taken and
usually denoted by ‘f’
7. MOLARITY
The number of the moles of solute present in a liter
of the solutions is known as molarity of the solution
SI unit of molarity=mole/L
MOLALITY
The number of the moles of solute present in one kg
of solvent is known as molality of the solution
molality= number of moles of solute
weight of solvent in kg
SI unit of molality=mole/kg
8. EquivalencePoint
The stage during the titration at which exactly equivalent amount of titrant is
added to titrand is known as equivalence point
In theatrical concept ,when equivalent amount of titrant is added to the titrand,
the indicator should change the colour and indicate the end point.
But in actual practice , the indicator doesn’t change its colour at equivalence
point. This is because the indicator changes its colour either in acidic or alkaline
medium.
Therefore in practice a small difference occurs between equivalence point and
end point. This difference in titration is known as titration error
11. VOLUMETRICANALYSIS
Volume of known concentration solution is used to find volume of unknown
concentration solution
Example: titration between strong acid (HCL) & Strong base (NaoH)
10ml =V1 ,0.1N HCL(known) End point: Point at which
Indicator-phenophthalain indicator shows color
change.
V2 “ x “ NaoH(unknown)
HCL = NaoH
N1 V1 = N2 V2
N1 X 10= N2 X 9
N2=0.1 X 10 =1 = 0.099N
9 9
12. REACTIONEMPLOYEDPROPERTIES INTITRIMETRICANALYSIS
MUSTFULFILLTHEFOLLOWINGCONDITION
The reaction must be simple and should be expressed by a simple chemical equation.
The reaction must be stoichiometric
The reaction should be rapid
There should be some change in physical or chemical properties at the end point of reaction.
A suitable indication which shows a change in its color or forms a precipitate at the end point should be available.
In the absence of an indicator change, some other physical properties like potential difference , conductance , adsorbance , ph
change etc… is measured using suitable instrument
14. REQUIREMENTS FORA SUBSTANCETO BEPRIMARY
STANDARD
it must be available in pure form and should be non toxic.
It should not be hygroscopic.
It should have high molecular weight so as to minimize the weighing error during weights.
It should be readily dissolve in water.
It should be stable. In other words , the composition of substance should not change in solid or in solution
state for long time.
15. PRIMARY STANDARD SUBSTANCE
The substance whose standard solution can
be prepared directly by dissolving the known
weight of the substance in fixed volume the
solution is known as primary standard
substance etc
Example: Anhydrous sodium
Carbonate,Oxalicacid, silver nitrate
etc………
The solution of primary standard
substance is called primary standard
solution
16. Secondarystandardsubstance
The substance whose solution can be standardize or strength can Be determined by the help of
primary standard solution is know as secondary standard substance and the solution is know as
secondary standard solution
Eg : NaOH , HCL , KMnO4
NORMALITY FACTOR :
It is defined as the ratio of actual weight of the substance taken to the theoretical weight of the
substance to be taken and usually denoted by “f” .
