Class 7 Exam > Class 7 Questions > Which of the following statements is correct?...
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Which of the following statements is correct?
- a)When coal is burnt no new substance is produced
- b)Rust is not formed in the absence of air or oxygen
- c)The fizz that comes out when a soda bottle is opened is due to a chemical change.
- d)Respiration is a physical process
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
Which of the following statements is correct?a)When coal is burnt no n...
For formation of rust both water vapour and oxygen are essential.
This question is part of UPSC exam. View all Class 7 courses
Most Upvoted Answer
Which of the following statements is correct?a)When coal is burnt no n...
Statement b) Rust is not formed in the absence of air or oxygen is correct.
Rust is a chemical compound that forms when iron or steel comes into contact with oxygen and moisture. The process of rusting is known as oxidation. It involves a chemical reaction where iron reacts with oxygen in the presence of water to form iron oxide, which is commonly known as rust.
Explanation:
Rust formation is a result of a chemical change, specifically an oxidation reaction. It does not occur in the absence of air or oxygen because oxygen is one of the essential components for rusting to take place. When iron or steel is exposed to oxygen in the presence of moisture, the iron atoms lose electrons and become oxidized, forming iron oxide.
Key Points:
- Rust formation requires the presence of oxygen and moisture.
- The reaction between iron or steel and oxygen in the presence of water leads to the formation of rust.
- In the absence of air or oxygen, rust cannot form.
- Rusting is a chemical change because it involves a chemical reaction where new substances are formed (iron oxide).
- Rusting can be prevented or slowed down by applying protective coatings, such as paint or oil, to prevent exposure to moisture and oxygen.
Conclusion:
The statement "Rust is not formed in the absence of air or oxygen" is correct because rusting is a chemical process that requires the presence of oxygen and moisture. In the absence of these components, rust cannot form.
Rust is a chemical compound that forms when iron or steel comes into contact with oxygen and moisture. The process of rusting is known as oxidation. It involves a chemical reaction where iron reacts with oxygen in the presence of water to form iron oxide, which is commonly known as rust.
Explanation:
Rust formation is a result of a chemical change, specifically an oxidation reaction. It does not occur in the absence of air or oxygen because oxygen is one of the essential components for rusting to take place. When iron or steel is exposed to oxygen in the presence of moisture, the iron atoms lose electrons and become oxidized, forming iron oxide.
Key Points:
- Rust formation requires the presence of oxygen and moisture.
- The reaction between iron or steel and oxygen in the presence of water leads to the formation of rust.
- In the absence of air or oxygen, rust cannot form.
- Rusting is a chemical change because it involves a chemical reaction where new substances are formed (iron oxide).
- Rusting can be prevented or slowed down by applying protective coatings, such as paint or oil, to prevent exposure to moisture and oxygen.
Conclusion:
The statement "Rust is not formed in the absence of air or oxygen" is correct because rusting is a chemical process that requires the presence of oxygen and moisture. In the absence of these components, rust cannot form.
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Which of the following statements is correct?a)When coal is burnt no new substance is producedb)Rust is not formed in the absence of air or oxygenc)The fizz that comes out when a soda bottle is opened is due to a chemical change.d)Respiration is a physical processCorrect answer is option 'B'. Can you explain this answer?
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