ANS:B - liquid

In the desorption of a highly soluble gas from a liquid, while the main resistance typically lies in the liquid phase, there can be situations where the resistance is primarily in the gas phase. Here's an explanation:

1. Liquid Phase Resistance: As mentioned earlier, in most cases, the main resistance in the desorption process of a highly soluble gas from a liquid is in the liquid phase. This is because the solubility of the gas in the liquid is high, leading to a significant concentration gradient between the liquid and gas phases. As a result, the gas molecules must diffuse through the liquid phase, which can create a resistance to mass transfer.
2. Gas Phase Resistance: However, there are scenarios where the main resistance may shift to the gas phase. This can occur when:
   • The desorption process involves reactions or physical phenomena in the gas phase that limit the transfer of gas molecules from the liquid to the gas phase.
   • The gas phase is poorly mixed or stagnant, leading to reduced contact between the gas and liquid phases.
   • The gas phase has a low concentration of the desorbing gas, leading to a low driving force for desorption.
   • The gas phase contains other components or impurities that hinder the desorption process.

In such cases, the resistance to mass transfer may be primarily in the gas phase, where the desorbing gas must overcome obstacles or limitations before it can effectively transfer from the liquid to the gas phase. Therefore, while the liquid phase is typically the main resistance in the desorption of a highly soluble gas from a liquid, there can be instances where the gas phase becomes the main resistance due to specific process conditions or factors.