This set of Corrosion Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Environments – Organic Acids”.
1. Which of the following materials is/are used for handling acetic acid?
a) Type 316 and 304 Stainless steels
b) Copper and Bronzes
c) Duriron and Hastelloy C
d) Hastelloy C, Durimet 20, Duriron, Copper, Bronzes and 316 and 304 stainless steels
View Answer
Explanation: Acetic acid is the most important organic acid from the standpoint of quantity produced. Hastelloy C, Durimet 20, Duriron, Copper, Bronzes, and 316 and 304 stainless steels are widely used for handling acetic acid.
2. Which of the following metals will switch positions in acetic acid as the temperature gets increased?
a) Copper and stainless steel
b) Stainless steel and nickel
c) Steel and copper
d) Aluminum and nickel
View Answer
Explanation: Acetic acid exhibits unusual corrosion behavior with an increase in temperature. Copper and stainless-steel switch positions as the temperature are increased. Copper shows little corrosion at high temperatures whereas stainless steels corrode rapidly and vice versa.
3. Organic acids are relatively weaker than the inorganic acids because they are slightly ionized.
a) True
b) False
View Answer
Explanation: Organic acids are relatively weaker than the inorganic acids because they are slightly ionized. The relatively high degree of ionization of inorganic acid results in greater electrochemical corrosion of metal.
4. Which of the following is the most corrosive organic acid?
a) Acetic acid
b) Formic acid
c) Ethanol
d) Acetone
View Answer
Explanation: Formic acid is one of the strongest and most corrosive organic acids. It mainly results in stress-corrosion cracking of various metals at various conditions. The chemical formula of formic acid is HCOOH.
5. Which of the following metal is prone to stress corrosion cracking in methanol?
a) Nickel
b) Copper
c) Titanium
d) Stainless steel
View Answer
Explanation: Methanol is the derivate of methane and it is also called methyl alcohol. The chemical of methanol is CH3OH. Titanium is prone to stress corrosion cracking in methanol with the presence of chloride impurities.
6. Which of the following metals will have high corrosion rates in aerated acetic acid?
a) Aluminum and its alloys
b) Copper and its alloys
c) Titanium and its alloys
d) Nickel and its alloys
View Answer
Explanation: Copper and its alloys will be highly affected by aeration (oxygen) in acetic acid and it increases with an increase in temperature. It can be prevented by deaeration and decrease in temperature.
7. Which of the following impurities that affect the corrosion rate of carbon steel in benzene solvent?
a) Oxygen
b) Butyric acid
c) Oxygen and butyric acid
d) Zinc dust
View Answer
Explanation: Oxygen and butyric acid are the impurities that affect the corrosion rate of carbon steel in benzene solvent. It can be prevented by eliminating oxygen.
8. What are the parameters that affect the corrosion rate of metal in organic acids?
a) Solvent composition
b) The solubility of corrosion products
c) Oxygen solubility
d) Solvent composition, the solubility of corrosion products and oxygen solubility
View Answer
Explanation: Parameters that affect the corrosion rate of metals in organic acids are:
i. Solvent composition and structure
ii. The solubility of corrosion products
iii. Oxygen solubility.
9. Which of the following is/are the corrosion prevention methods in organic acids?
a) Selection of materials and drying
b) Selection of materials, drying, deaeration, and neutralization of the solvent
c) Deaeration and neutralization of the solvent
d) Drying and deaeration
View Answer
Explanation: Corrosion prevention methods in organic acids:
i. Selection of materials
ii. Drying
iii. Deaeration
iv. Neutralization of the solvent.
10. The application of electrochemical protection methods in organic acids is restricted due to low electrical conductivity.
a) True
b) False
View Answer
Explanation: Application of electrochemical protection methods in organic acids is restricted due to low electrical conductivity. As we know cathodic and anodic protection is based on electrical conductivities of metallic structure and medium.
Sanfoundry Global Education & Learning Series – Corrosion Engineering.
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