Why does thick chemically weathered soil form less in dry regions despite mechanical weathering?

Correct answer: Because lack of water limits chemical alteration

Water acts as both a solvent and a medium for chemical reactions in weathering. When water is scarce, processes such as hydration, hydrolysis and solution become very slow, so thick chemically weathered soil develops less readily. Mechanical weathering may break rocks through thermal expansion or salt crystallisation, but it does not itself cause chemical alteration. Exam tip: associate arid climates mainly with mechanical weathering and limited chemical weathering.