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UPSC NDA 2 2016 General Ability Solved Paper

Question : 52 of 150

Marks: +1, -0

The following 6 (Six) items consist of two statements, Statement I and Statement II. Examine these two statements carefully and select the correct answer using the code given below.

Statement I: Ozone is a triatomic molecule of oxygen.

Statement II: Ozone is concentrated mainly in the stratosphere.

Both the statements are individually true and Statement II is the correct explanation of Statement I
Both the statements are individually true but statement II is not the correct explanation of Statement I
Statement I is true but Statement II is false
Statement I is false but Statement II is true

Validate

Solution:

Concept:

Ozone (

\mathrm{O}_3

) is a form of oxygen with three atoms and is found mostly in the stratosphere, but these two facts are independent of each other.

Explanation:

Statement I says ozone is a triatomic molecule of oxygen.

This is correct because ozone's chemical formula is

\mathrm{O}_3

, meaning it contains three oxygen atoms bonded together.

So Statement I is true.

Statement II says ozone is concentrated mainly in the stratosphere.

This is also correct — about 90% of Earth's ozone is located in the stratosphere, where it forms the ozone layer that absorbs harmful ultraviolet (UV) radiation from the Sun.

So Statement II is true as well.

However, Statement II does not explain why ozone is a triatomic molecule of oxygen.

The fact that ozone is found in the stratosphere is about its location, not about its molecular structure.

The two statements are individually true but unrelated as cause and effect.

Answer:

Both the statements are individually true but Statement II is not the correct explanation of Statement I.

Hence, the correct option is B.

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