Rust is the deposition of reddish-brown ferric oxide on the surface of the iron. It is formed by the reaction of iron with oxygen and moisture. It makes iron brittle and frail, reducing its potency and permeability. Various factors like moisture, acid and salt increase the rate of rusting.
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Definition: Rust is the reddish-brown iron oxide formed by the reaction of iron with oxygen in the presence of moisture (water). The chemical formula of rust is Fe2O3. xH2O. |
The Chemical formula of Rust Chemistry Questions with Solutions
Q1. What is the chemical formula od rust?
(a) Fe2O3. xH2O
(b) Fe3O4. xH2O
(c) Both (a) and (b)
(d) None of the above
Answer: (a) Fe2O3. xH2O
Q2. What is the colour of rust?
(a) Reddish-brown
(b) Greenish-yellow
(c) Both (a) and (b)
(d) None of the above
Answer: (a) Reddish-brown
Q3. What is the nature of rust?
(a) Acidic
(b) Basic
(c) Both (a) and (b)
(d) None of the above
Answer: (b) Basic
Explanation: Rust is a metal oxide. Hence, it is basic.
Q4. Rusting of iron is also known as ________.
(a) Corrosion
(b) Ferrisation
(c) Both (a) and (b)
(d) None of the above
Answer: (a) Corrosion
Q5. What is the chemical name of rust?
(a) Ferrous oxide
(b) Ferric oxide
(c) Both (a) and (b)
(d) None of the above
Answer: (b) Ferric oxide
Q6. What is rusting?
Answer: Rusting refers to the deposition of reddish brown material on iron articles. It damages or destroys the iron material.
Q7. What is galvanisation?
Answer: Galvanisation refers to the application of a protective zinc layer on iron or steel articles to prevent rusting.
Q8. What are the causes of rusting?
Answer: Rust is the deposition of reddish-brown ferric oxide on the surface of the iron. It is formed by the reaction of iron with oxygen and moisture. It erodes the iron object.
Q9. What are the various factors that affect rusting of iron?
Answer: Various factors that affect the rusting of iron are mentioned below.
1. Presence of moisture
2. Presence of acid
3. Presence of salt
4. Adulteration (Impure iron)
Q10. How does moisture content affect the rusting of iron?
Answer: Moisture content is directly related to rusting. The larger the moisture, the more would be rusting. The moisture reacts with electrons on the surface of the metal, leading to a redox reaction forming the ferric oxide.
Q11. What is the effect of pH on the rusting of iron?
Answer: pH is inversely proportional to rusting. The rusting process will slow if the pH of the environment surrounding the metal is significant.
Q12. How does the presence of salt affect the rusting of iron?
Answer: The rusting of iron speeds up in the presence of salt. Salt act as an electrolyte. It will allow the iron to lose its electrons rapidly.
Q13. What is the primary difference between rusting and corrosion?
Answer: The primary difference between rusting and corrosion is that rusting occurs on the surface of iron and its articles, but corrosion occurs on multiple surfaces such as metal, wood, marble, etc.
Q14. Name any three metals which do not corrode.
Answer: Platinum, gold and silver are the three metals which do not corrode.
Q15. Match the following.
|
Column A |
Column B |
|---|---|
|
Corrosion of bridges |
Redish-Brown |
|
Rust |
Acid Rain |
|
Salt |
Electrochemical phenomenon |
|
Corrosion |
Increase rusting |
Answer:
|
Column A |
Column B |
|---|---|
|
Corrosion of bridges |
Acid Rain |
|
Rust |
Redish-Brown |
|
Salt |
Increase rusting |
|
Corrosion |
Electrochemical phenomenon |
Practise Questions on The Chemical formula of Rust
Q1. What is the effect of impurity on rusting of iron?
Q2. Write the reactions involved during the rusting of iron.
Q3. Why is rusting of iron an unpleasant phenomenon?
Q4. Name an alloy of iron that does not rust.
Q5. What are the constituents of stainless steel?
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