Consider the following statements : Statement-I : Rainfall is one of

Consider the following statements :

Statement-I : Rainfall is one of the reasons for weathering of rocks.
Statement-II : Rain water contains carbon dioxide in solution.
Statement-III : Rain water contains atmospheric oxygen.

Which one of the following is correct in respect of the above statements?

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Both Statement-II and Statement-III are correct and both of them explain Statement-I

Both Statement-II and Statement-III are correct, but only one of them explains Statement-I

Only one of the Statements II and III is correct and that explains Statement-I

Neither Statement-II nor Statement-III is correct

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC IAS – 2024

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Statement-I is correct. Rainfall is a major agent of weathering. This includes physical weathering (e.g., the impact of raindrops, wetting and drying cycles) and chemical weathering. Statement-II is correct. Rainwater absorbs carbon dioxide from the atmosphere, forming weak carbonic acid (H₂CO₃) in solution. Statement-III is correct. Rainwater also absorbs oxygen from the atmosphere. Both carbon dioxide (as carbonic acid) and oxygen dissolved in rainwater contribute significantly to chemical weathering processes. Carbonic acid reacts with minerals like calcium carbonate (carbonation), and dissolved oxygen causes oxidation of iron-bearing minerals (oxidation). Therefore, both Statement-II and Statement-III describe components of rainwater that are responsible for chemical weathering, which is a type of weathering caused by rainfall. Thus, both statements are correct and both explain Statement-I by describing mechanisms through which rainfall causes weathering.

– Rainfall causes both physical and chemical weathering.
– Chemical weathering involves reactions between rock minerals and substances in rainwater.
– Carbon dioxide in rainwater forms carbonic acid, causing carbonation.
– Oxygen in rainwater causes oxidation.

Chemical weathering is particularly effective in warm and humid climates where rainfall is abundant. The presence of dissolved substances like CO2 and O2 in rainwater significantly enhances its chemical reactivity with rocks.

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