This set of Chemical Process Technology Interview Questions and Answers focuses on “Natural Products – Paints, Varnishes & Pigments”.
1. Manufacturing of paints involves unit processes. Is the statement true/false?
a) True
b) False
View Answer
Explanation: The statement is wrong as manufacturing of paints, varnishes, and lacquers involves only unit operations but not unit processes. Pigments and resins manufacturing involves chemical reactions, hence unit processes.
2. Solvent used in varnishes is ________
a) Water
b) Oil
c) Alcohols
d) Ethers
View Answer
Explanation: Water is a solvent for water-based paints. Oil is a solvent for oil-based paints and varnishes. Ethers, alcohols are solvents for lacquers.
3. Anti-foam agent in water-based paints is ___________
a) Casein
b) Pine oils
c) Chlorinated phenols
d) Poly hydroxyl phenols
View Answer
Explanation: Casein is the dispersing agent, pine oil is the anti-foam agent, and chlorinated phenols are the preservatives in the water-based paints. Poly hydroxyl phenols are used as the anti-skinning agents.
4. Which type of surface coating doesn’t use diluents?
a) Oil-based paints
b) Lacquers
c) Varnishes
d) Water-based paints
View Answer
Explanation: Water-based paints doesn’t require diluents where as oil-based paints, lacquers, and varnishes uses naphtha’s and turpentine as diluents (thinner).
5. Agglomeration is a mode of drying in _________________
a) Water-based paints
b) Enamels
c) Oil-based paints
d) Lacquers
View Answer
Explanation: Evaporation and agglomeration are modes of drying of ware-based paints. Oxidation and polymerization are modes of drying of oil-based paints and varnishes. Lacquers mode of drying is evaporation.
6. Which of the following is a colored pigment?
a) Zinc oxide
b) Lithopone
c) Lead chromate
d) Titanium dioxide
View Answer
Explanation: White lead, lithopone, zinc oxide, titanium dioxide are all white pigments. Lead chromates, Prussian blue, and different iron oxides are colored pigments.
7. Which of the following pigment is an anti-corrosive pigment?
a) Prussian blue
b) Zinc chrome
c) Titanium dioxide
d) Carbon black
View Answer
Explanation: Apart from prime pigments Ultramarine blue, Prussian blue, phthalocyanine blue, titanium dioxide, carbon black etc anti-corrosive pigments like zinc chrome and basic lead sulfates are developed.
8. What percentage of zinc oxide is present in a typical exterior white paint?
a) 15% ZnO
b) 50% ZnO
c) 25% ZnO
d) 10% ZnO
View Answer
Explanation: A typical exterior white paint contains 15% TiO2, 25%ZnO, 50% white lead, and 10% pigment extender. Paint with this composition has self cleaning feature by a process called chalking process.
9. Temperature at which the reaction TiCl4 + O2 → TiO2 + 2Cl2 takes place is __________
a) 500°C
b) 1500°C
c) 1000°C
d) 2000°C
View Answer
Explanation: Temperature at which the reaction TiCl4 + O2 → TiO2 + 2Cl2 takes place is 1500°C. Specially designed refractory lined furnaces are used. Chlorine is recovered for recycle.
10. Rutile grade titanium dioxide is produced in _____________
a) Travancore titanium products limited (TTP)
b) Kilburn chemicals limited
c) Kolmak chemicals limited
d) Kerala minerals and metals limited (KMML)
View Answer
Explanation: Travancore titanium products limited (TTP), Kilburn chemicals limited, Kolmak chemicals limited produces titanium dioxide pigment using sulfate route whereas Kerala minerals and metals limited (KMML) produces rutile grade titaniium oxide.
11. Oils are used for dual purpose in surface coating formulation.
a) True
b) False
View Answer
Explanation: The statement is true as oils are used as carriers for pigments and as formers of the protective films. Hence they serve a dual purpose in surface coating formulation.
12. Semi-drying oil is ____________
a) Linseed
b) Soya bean oil
c) Coconut oil
d) Castor oil
View Answer
Explanation: Based on degree of unsaturation, oils are classified as drying oils and semi-drying oils. Examples of drying oils are linseed, soya bean, castor oil, Tung oil, and tall oil. Examples of semi-drying oils are coconut oil, tobacco seed etc.
13. Resins are not used in _____________
a) Oil-based paints
b) Water based paints
c) Varnishes
d) Lacquers
View Answer
Explanation: Oil based paints doesn’t use resins. Water based paints doesn’t use oils and depend on resins as film forming materials. Lacquers and varnishes use alkyd resins, phenolic etc.
14. Natural solvents for paints in India is __________________
a) Pine oil
b) Turpentine
c) Citrus solvent
d) Tung oil
View Answer
Explanation: In India the natural solvent is turpentine. Pine oil and dipentene production is done from turpentine. Synthetic solvents such as butyl alcohol, butyl acetate etc are developed.
15. Which of the following is a natural resin?
a) Alkyds
b) Vinyl resins
c) Silicone resins
d) Rosin
View Answer
Explanation: African copal or rosin, shellac, and cashew nut shell are the natural resins in India. Alkyds, Vinyl resins, Silicone resins, phenolic resins etc are the synthetic resins.
Sanfoundry Global Education & Learning Series – Chemical Process Technology.
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