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?
A
Both Statement-II and Statement-III are correct and both of them explain Statement-I
Correct Answer
B
Both Statement-II and Statement-III are correct, but only one of them explains Statement-I
C
Only one of the Statements II and III is correct and that explains Statement-I
D
Neither Statement-II nor Statement-III is correct
Explanation
Option (a) is correct because rainwater facilitates chemical weathering through carbonation (via dissolved $CO_2$ forming weak carbonic acid) and oxidation (via dissolved atmospheric oxygen), both of which directly cause the decomposition of rock minerals. Option (b) is the most tempting wrong choice as it incorrectly assumes only one of these gases contributes to weathering, whereas both are fundamental agents in the chemical breakdown of rocks. The core concept tested is the mechanism of chemical weathering and the role of atmospheric gases in the rock cycle.
GeomorphologyWeathering and Mass MovementsWeathering of rocksRain waterCarbon dioxideAtmospheric oxygenChemical weathering