The correct option is B. the mineral composition of rock is changed in chemical weathering. Explanation of the Correct Answer Chemical Weathering refers to the process where rocks undergo chemical changes, leading to the alteration of their mineral composition. This can occur through various chemical reactions, such as hydrolysis, oxidation, and carbonation. For example, when carbon dioxide (CO2) in the atmosphere dissolves in rainwater, it forms carbonic acid, which can react with minerals like feldspar in granite, converting it into clay minerals. This process fundamentally changes the minerals present in the rock. In contrast, Physical Weathering (also known as mechanical weathering) involves the breakdown of rocks into smaller pieces without altering their chemical composition. This can occur through processes such as freeze-thaw cycles, where water seeps into cracks in the rock, freezes, expands, and eventually causes the rock to fracture. The original minerals remain unchanged; they are simply broken into smaller fragments. Why the Other Options are Incorrect A. There is a change in the mineral composition of rock in physical weathering. - This statement is incorrect because physical weathering does not change the mineral composition of the rock. It only breaks the rock into smaller pieces while retaining the same minerals. For example, if granite is physically weathered, it will still be granite, just in smaller pieces. C. Carbonation is necessary in physical weathering. - This option is misleading. Carbonation is a chemical weathering process where carbon dioxide reacts with minerals to form carbonates. It is not a process involved in physical weathering. Physical weathering can occur due to mechanical forces like temperature changes, water, or wind, but it does not require carbonation. D. Wind is necessary in chemical weathering. - This statement is also incorrect. While wind can contribute to physical weathering (for example, by eroding rocks through abrasion), it is not a necessary factor in chemical weathering. Chemical weathering primarily involves chemical reactions that can occur in the presence of water, acids, or other reactive substances, independent of wind. Summary of Key Points

• Chemical Weathering changes the mineral composition of rocks through chemical reactions, while Physical Weathering breaks rocks into smaller pieces without altering their composition.
• Examples of chemical weathering include hydrolysis and oxidation, while physical weathering includes freeze-thaw cycles and abrasion.
• Understanding the distinction between these two types of weathering is crucial for studying soil formation, landscape evolution, and the rock cycle.

Revision Summary

• Chemical weathering alters the mineral composition of rocks; physical weathering does not.
• Key processes in chemical weathering include hydrolysis and carbonation.
• Physical weathering involves mechanical processes like freeze-thaw cycles and does not involve chemical changes.
• Recognizing the differences between these weathering types is essential for understanding geological and environmental processes.