The correct answer is option 2, hot and humid climate. Chemical weathering is a process that breaks down rocks through chemical reactions. In a hot and humid climate, there is an abundance of moisture in the air, leading to increased chemical reactions. The combination of heat and humidity accelerates the chemical processes that break down rocks.

Option 1, cold and dry climate, would not result in as much chemical weathering. Cold temperatures generally slow down chemical reactions, and a lack of moisture in the air reduces the availability of water for chemical reactions to occur.

Option 3, hot and dry climate, also does not favor chemical weathering as much as a hot and humid climate. While heat can increase the rate of chemical reactions, a lack of humidity means there is less moisture available to participate in the chemical processes.

Option 4, cold and humid climate, may have some level of chemical weathering due to the presence of moisture. However, the cold temperatures would slow down the rate of chemical reactions, limiting the overall extent of weathering.

In summary, a hot and humid climate is the most conducive environment for chemical weathering due to the combination of high temperatures and abundant moisture.