1. Choose the condition in which a silver cup will tarnish.

A. Presence of sulphur in air and coated with oil
B. Presence of oxygen in air and coated with oil
C. Presence of sulphur in air and coated with water
D. Presence of oxygen in air and coated with grease

2. Explain with an example why corrosion is a harmful chemical process and write 2 ways to prevent it.

3. Which place is likely to have a greater chance of corrosion - a place with 40% humidity or a place with 60% humidity? Give reasons for your answer.

A silver cup will tarnish in the presence of sulfur in air and coated with water. Corrosion is harmful as it leads to material degradation and can be prevented by using protective coatings and sacrificial anodes. A place with 60% humidity has a greater chance of corrosion than one with 40% humidity due to the increased moisture levels.
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Answered by Anonymous | 2025-07-16

Choose the condition in which a silver cup will tarnish.

The correct answer is (C) Presence of sulphur in air and coated with water.

Silver tarnishes when it comes into contact with hydrogen sulfide (a form of sulfur present in the air) and moisture. This results in a black layer of silver sulfide forming on the surface.


Explain with an example why corrosion is a harmful chemical process and write 2 ways to prevent it.

Corrosion is harmful because it deteriorates materials, especially metals, weakening structures and leading to significant economic losses. An example is the rusting of iron, which can cause bridges or buildings to become unsafe over time.
Two ways to prevent corrosion are:

Coating : Applying protective coatings, such as paint or oil, to metal surfaces prevents direct contact with corrosive elements.

Galvanization : This involves coating iron or steel with a layer of zinc. Zinc acts as a protective barrier and also sacrifices itself to protect the underlying metal if it's scratched.

Which place is likely to have a greater chance of corrosion - a place with 40% humidity or a place with 60% humidity? Give reasons for your answer.


A place with 60% humidity is more likely to experience higher levels of corrosion compared to a place with 40% humidity.

Humidity provides moisture, an essential factor for many corrosion processes, including rusting in iron. Higher humidity increases the amount of water vapor available for chemical reactions that lead to corrosion, thus accelerating the process.

Answered by JessicaJessy | 2025-07-21