Chemistry Project on Preparation of Pigments and Poster Paints
To Prepare Pigments and Poster Paints Using Various Chemicals and Reagents
Certified that Pujit Singh of XII-C has accomplished this project under the supervision and guidance of Mr. Harsh Gupta.
Acknowledgement
I would like to show my gratitude to my Chemistry teachers Ms. Anita Sood and Mr. Harsh Gupta, without whose support and encouragement this project could never have taken the present shape. I would also like to thank my lab incharge Mr. Vinod for helping me out during the practical part of this project.
Aim
To prepare pigments and poster paints using various chemicals and reagents.
Theory
1. Pigments: A pigment is a finely divided material which contributes to optical and other properties of paints. Pigments may be classified according to their composition or source from which they are obtained. However, the most common and useful classification is that color pigments can be made using simple chemical reactions and techniques.
2. Poster Paints: Grinding a pigment or a mixture to a very fine powder and then suspending the powder in a liquid makes poster paint so as to form a uniform suspension. For making poster paints, the pigments made by various chemical reactions are thoroughly mixed with the medium. Sometimes the paint hardens, but the addition of lukewarm water to it can soften it.
3. Medium: Medium used for making paints is made by mixing 30 ml of clear glue with 10 ml of water and adding a drop of liquid detergent to it.
Chrome Yellow
Chemically known as Lead Chromate (PbCrO4), the yellow pigment is obtained as follows:
Procedure:
- Dissolve 7 g of Potassium Chromate in 50 mL water and 10 g Lead Nitrate in 100 mL water in two separate beakers.
- Pour the Potassium Chromate solution into the Lead Nitrate solution and stir continuously.
- Lead Chromate separates as a precipitate and is the required pigment.
- Filter the precipitate and dry the pigment.
Reaction Involved:
K2CrO4 + Pb(NO3)2 → PbCrO4 + 2KNO3
Efficiency of Chrome Yellow
Total mass of reactants used (excluding the mass of water used for dilution) =
Mass of paint/pigment obtained =
Efficiency in formation of yellow colour =
Prussian Blue
Chemically known as Complex Ferro Cyanide (Fe4[Fe(CN)6]3).
Procedure:
- Make a solution of 5 g of hydrated Iron(III) Chloride in 50 mL of water.
- Make a solution of 10 g of Potassium Ferrocyanide in 75 mL of water.
- Add the Iron Chloride solution into the Potassium Ferrocyanide (K4[Fe(CN)6]) solution while stirring briskly.
- A dark blue, very fine powdered substance precipitates.
- Filter the precipitate and wash it with water. It takes a long time to filter this substance.
Reaction Involved:
3K4[Fe(CN)6] + 4FeCl3 → Fe4[Fe(CN)6]3 + 12KCl
Efficiency of Prussian Blue
Total mass of reactants used (excluding mass of water used for dilution) =
Mass of paint/pigment obtained =
Efficiency in formation of blue pigment =
Conclusion
Fine poster paints were obtained using various chemicals and reactants.