Consider the following statements: Statement-I: Rainfall is one of the reasons for the 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?
- A.Both Statement-II and Statement-III are correct and both of them explain Statement-I
- B.Both Statement-I and Statement-II are correct, but only one of them explains Statement-I
- C.Only one of the Statement II and III is correct and that explain Statement- I
- D.Neither Statement-II nor Statement-III is correct
▶ Answer & Explanation
Correct answer: A. Both Statement-II and Statement-III are correct and both of them explain Statement-I
Rainfall directly contributes to physical weathering through processes like freeze-thaw action and hydraulic action. Chemically, rainwater acts as a solvent, and its dissolved carbon dioxide forms carbonic acid, which is a potent agent in chemical weathering, particularly for carbonate rocks like limestone. Atmospheric oxygen dissolved in rainwater also participates in oxidation reactions, a form of chemical weathering affecting iron-bearing minerals.
Source: UPSC gs1 2024