Two factors that promote rapid chemical weathering in the tropics are

Chemical weathering is the breakdown of rocks through chemical reactions such as hydrolysis, carbonation, oxidation, and solution. Two factors that greatly accelerate these reactions in the tropics are high temperature and high humidity.

• High temperature increases the rate of chemical reactions. As a general rule, a 10 °C rise in temperature roughly doubles the rate of most chemical reactions. The consistently warm temperatures in the tropics keep these reactions occurring rapidly throughout the year.
• High humidity (and abundant rainfall) ensures a constant supply of water, which is essential for chemical weathering processes. Water acts as a solvent and a reactant in hydrolysis and carbonation. Rainwater absorbs carbon dioxide from the atmosphere and soil to form weak carbonic acid, which dissolves minerals in rocks.

Low temperature would slow chemical reactions. Extreme aridity or low humidity would remove the water needed for these chemical processes to occur. This is why chemical weathering is most intense in hot, humid tropical environments and weakest in cold or arid regions.