This set of Applied Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Protective Coatings”.
1. The protective coatings are used to ___________
a) Corrode the metal
b) Prevent from corrosion
c) Increase the corrosion
d) Slightly increase the corrosion
Explanation: The protective coatings are used to prevent the corrosion of the metal. The protective layers are thin layer on the surface of the metal.
2. The oxidation resistance is given by the protective coatings.
Explanation: The protective layer is used to provide the oxidation resistance to the metal and to give thermal insulating properties of the metal.
3. In sand blasting, the atmospheric pressure is about __________
Explanation: In sand blasting, the atmospheric pressure is about 25-100atm. The sand blasting will blast with sand particles of different sizes.
4. The cleaning methods before applying the protective coating are of _________ types.
Explanation: The cleaning methods before applying the protective coating are of 6 types. They are: solvent cleaning, alkali cleaning, mechanical cleaning, flame cleaning, sand blasting and pickling and etching.
5. In anodic coatings, the coating metals possess __________ reduction potential than base metal.
d) Cannot be said
Explanation: In anodic coating, the coating metals possess the lower reduction potential than base metal. The coating metals possess the higher reduction potential than base metal.
6. Tinning is the example of __________
a) Anodic coatings
b) Cathodic coatings
c) Neither anode nor cathode
d) Both anode and cathode
Explanation: Tinning is an example of the cathodic coatings. The galvanisation comes under the anodic coatings.
7. During the sand blasting process, the workers are affected by the disease called _________
b) Chicken guinea
c) Blue baby syndrome
Explanation: During the sand blasting process, the workers are affected by the disease called as the silicosis. It is one the main disadvantages of this method.
8. In pickling and etching _________ acids are used.
a) Sulphuric acid
b) Hypo chlorous acid
c) Phosphoric acid
d) Phosphorous acid
Explanation: In pickling and etching process, the acids used are hydrochloric acid, sulphuric acid and nitric acid.
9. The old paint coating cannot be removed by __________
b) Caustic soda
c) Trisodium phosphate
d) Sulphuric acid
Explanation: The old paint coatings can be removed by alkali cleaning process. The Soaps, caustic soda and trisodium phosphate are used.
10. The process of coating iron or steel sheet with a thin coat of zinc to prevent iron from rusting is called ____________
c) Metal cladding
Explanation: The process of coating iron or steel sheet with a thin coat of zinc to prevent iron from rusting is called galvanisation. The process of depositing the coating metal on the surface of base metal by electrolysis is called electroplating.
Sanfoundry Global Education & Learning Series – Applied Chemistry.
To practice all areas of Applied Chemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.