UPSC Prelims 2024 · Question 57 of 97
UPSC Prelims 2024 question on Rainfall and Rock Weathering
- ExamUPSC CSE
- Year2024
- PaperGeneral Studies Paper I
- SubjectGeography
- TopicGeomorphology
- DifficultyHard
- TypeAssertion
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?
Show answer
Answer: A. Both Statement-II and Statement-III are correct and both of them explain Statement-I
Verdict
Correct answer: Both Statement-II and Statement-III are correct and both explain Statement-I → Option (a).
Statement by statement
Statement I – CORRECT: Chemical weathering is the basic process by which denudation proceeds. Rainfall is indeed one of the reasons for weathering of rocks.
Statement II – CORRECT: Rain water contains carbon dioxide in solution. As with rain-water, it contains enough carbon dioxide to make it a weak acid. Solution is the most potent weathering process in limestone regions. Hence Statement II is correct and explains Statement I.
Statement III – CORRECT: Dissolved oxygen is present in all rainwater and surface supplies due to contact with the atmosphere. Oxidation is the reaction of oxygen in air or water with minerals in the rock. Most rocks contain a certain amount of iron, which when it comes in contact with air is changed to iron oxide. Hence Statement III is correct and also explains Statement I.