Rain (chemical) is an example of chemical weathering.

• A. Rain (chemical)
• B. Root pry
• C. Frost action
• D. Wind

Answer: (A)

Chemical weathering happens when a substance reacts with minerals in rocks to change their composition. Rain can drive chemical weathering because rainwater contains dissolved carbon dioxide (and other acids) that react with minerals in rocks, leading to dissolution and hydrolysis. Over time this creates new minerals like clays and dissolves ions, gradually weakening the rock. That’s why Rain (chemical) is the best example of chemical weathering.

The other processes are physical weathering: root pry uses plant roots to wedge rocks apart, frost action relies on ice expanding in cracks to split rocks, and wind mainly abrades surfaces without causing chemical changes to the minerals themselves.