UPSC Previous Year Question | Prelims GS | 2024

Consider the following statements: Statement-I: Rainfall is one of the reasons for weathering of rocks. Statement-II: Rainwater contains carbon dioxide in solution. Statement-III: Rainwater contains atmospheric oxygen. Which one of the following is correct in respect of the above statements?

  1. Both Statement-II and Statement-III are correct and both explain Statement-I.
  2. Both Statement-II and Statement-III are correct, but only one of them explains Statement-I.
  3. Only one of Statements II and III is correct and that explains Statement-I.
  4. Neither Statement-II nor Statement-III is correct.

Answer

Correct Answer

Both Statement-II and Statement-III are correct and both explain Statement-I.

Explanation

Rainwater contains dissolved carbon dioxide, which forms weak carbonic acid and promotes chemical weathering of rocks. It also contains dissolved atmospheric oxygen, which contributes to oxidation of susceptible minerals. Both Statement-II and Statement-III are correct and help explain how rainfall contributes to weathering.

Topics: chemical weathering, geography, geomorphology, weathering