The document provides an overview of gravimetric analysis, defined as a quantitative method that isolates and weighs a specific element or compound. It outlines the types of gravimetric methods, including electrogravimetry, volatilization gravimetry, and particulate gravimetry, along with the key characteristics of precipitating agents and organic precipitants. Additionally, it emphasizes the importance of using representative and homogeneous samples in gravimetric analysis.

1. By- SANCHIT DHANKHAR
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2. Topic to be Discuss
 Definition
 Principle
 Instrumentation/ Methodology
 Applications
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3. DEFINATION
It is a type of quantitative analysis that involves weighing of the constituent
under determination.
Or
It is the process of isolating and weighing an element or compound in a pure
form.
Or
Gravimetric methods of analysis are based on the measurement of mass.

4. Example:
 Determination of lead (Pb+2) in water
Pb+ + 2Cl-  PbCl2(s)
 By adding excess Cl- to the sample,
essentially all of the Pb+2 will precipitate as
PbCl2.
 Mass of PbCl2 is then determined.
- used to calculate the amount of Pb+2 in
original solution
Reagent
Analyte Solid Product
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5. Types of Gravimetric Methods
 Electrogravimetry, we deposit the analyte as a solid film an electrode in an
electrochemical cell.
Ex: The deposition as PbO2 at a Pt anode and reduction of Cu2+ to Cu at a Pt
cathode is of electrogravimetry.
 When thermal or chemical energy is used to remove a volatile species, such
method called as Volatilization gravimetry.
Ex: In determining the moisture content of bread, for example, we use
thermal energy to vaporize the water in the sample.
 Particulate gravimetry we determine the analyte by separating it from the
sample’s matrix using a filtration or an extraction. The determination of total
suspended solids is one example of particulate gravimetry.
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6. Steps involved in Gravimetric Analysis

7. Desirable properties of analytical
PRECIPITATES
 Readily filtered and purified
 Low solubility, preventing losses during filtration and washing
 Stable final form (un-reactive)
 Known composition after drying or ignition
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8. Ideal characteristic of Precipitating agent
A gravimetric precipitating agent should react
specifically, and selectively with the analyte. The
ideal precipitating reagent would react with the
analyte to give a product that is
 Readily filtered and washed free of
contaminants
 Low solubility so that no significant loss of
the solid occurs during filtration and
washing
 Un-reactive with constituents of the
atmosphere
 Should not alter the composition after it is
dried or, if necessary, ignited.
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9. •
Dimethylglyoxime
(DMG)- Ni, Pd
• 8 Hydroxy
quinoline- Mg, Al
• Cupferron- Cu,
Fe
• Benzidine-
sulphate
• Arsonic acid- Tin
(Sn)
Organic Precipitating
Agents
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10. Organic Precipitants
Many organic ions can be precipitated with certain organic reagents
referred as Organic precipitants.
Most of the organic precipitants combine with the Cation to form chelate
rings, Many such chelate rings are neutral compounds which are
insoluble in water.
Advantage:
1. Chelate are form are highly water insoluble, which help in the
quantitative analysis of metal ions.
2. High molecular weight hence small amount is more of to carry out
the precipitation reaction, and minimize the error in weighing.
3. High selectivity
Disadvantage:
Some time organic precipitants itself contaminated with the
precipitate because of the former’s limited solubility in water.

11. Preparation of solution/ Sampling
 A sample is portion of material selected which posses essential
characteristic of the bulk of the material and is in the form of a fine
powder.
 The sample weight for the gravimetric analysis are usually very small.
 The sample should be representative and homogeneous
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12. THANKYOU
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