1. In corrosion the chemical reaction is
(A) reduction
(B) displacement
(C) decomposition
(D) oxidation
2. Which one of the following causes corrosion of iron
(A) oxygen
(B) hydrogen
(C) strong base
(D) moisture and oxygen
3. The colour of corrosion product of silver is
(A) black
(B) silver white
(C) green
(D) grey
4. The colour of corrosion product of copper is
(A) silver white
(B) black
(C) green
(D) grey
5. Which one of the following metal does not corrode
(A) zinc
(B) magnesium
(C) sodium
(D) platinum
6. The chemical composition of rust is
(A) FeO·H₂O
(B) Fe₂O₃·xH₂O
(C) Fe(OH)₃
(D) Fe(OH)₂
7. Machining, forming, welding, or heat treatment of metal can cause
(A) stress corrosion
(B) uniform corrosion
(C) pitting corrosion
(D) dry corrosion
8. A common corrosion which deteriorates the whole surface of the metal and makes the surface thin is
(A) stress corrosion
(B) uniform corrosion
(C) pitting corrosion
(D) dry corrosion
9. The corrosion due to the movement of corrosive liquids is
(A) stress corrosion
(B) pitting corrosion
(C) erosion corrosion
(D) soil corrosion
10. The corrosion of underground pipes, cables etc. is called
(A) soil corrosion
(B) erosion corrosion
(C) pitting corrosion
(D) stress corrosion
11. The corrosion of iron is called
(A) soil corrosion
(B) erosion corrosion
(C) galvanic corrosion
(D) rust
12. The corrosion which makes deep holes is called
(A) erosion corrosion
(B) pitting corrosion
(C) crevice corrosion
(D) soil corrosion
13. Corrosion on the surface of a metal due to direct reaction of atmospheric gases is
(A) stress corrosion
(B) dry or chemical corrosion
(C) crevice corrosion
(D) soil corrosion
14. The organisms causing the greatest corrosion problems are
(A) bacteria and fungi
(B) algae and fungi
(C) viruses and bacteria
(D) viruses and fungi
15. A process in which metal is protected from corrosion by dipping it in molten zinc is called
(A) tinning
(B) cladding
(C) electroplating
(D) galvanization
16. A process in which metal is protected from corrosion by cementing zinc powder is called
(A) calorizing
(B) chromizing
(C) galvanization
(D) sherardizing
17. A process in which the coat metal is deposited on the base metal by passing a direct current is called
(A) electroplating
(B) cladding
(C) galvanization
(D) tinning
18. A cementation with 55% chromium powder & 45% alumina for protection from corrosion is called
(A) calorizing
(B) sherardizing
(C) chromizing
(D) galvanization
19. A cementation with aluminium and alumina powder for protection from corrosion is called
(A) chromizing
(B) sherardizing
(C) galvanization
(D) calorizing
20. The bonding together of dissimilar metals by pressure is called
(A) calorizing
(B) chromizing
(C) galvanization
(D) cladding