ANS:B - decreases

With an increase in solvent rate, the number of transfer units, 𝑁𝑡𝑜𝐺NtoG​, for a fixed degree of absorption from a fixed amount of gas typically decreases. Explanation:

• The number of transfer units, 𝑁𝑡𝑜𝐺NtoG​, is a measure of the efficiency of mass transfer in a gas-liquid absorption process. It represents the number of theoretical equilibrium stages required for a given degree of mass transfer.
• In gas-liquid absorption processes, such as gas absorption or stripping, increasing the solvent rate typically enhances mass transfer by providing more contact between the gas and liquid phases.
• With a higher solvent rate, there is increased contact area between the gas and liquid phases, which promotes more efficient mass transfer and reduces the number of theoretical equilibrium stages required to achieve the same degree of absorption.
• Therefore, as the solvent rate increases, the number of transfer units, 𝑁𝑡𝑜𝐺NtoG​, for a fixed degree of absorption from a fixed amount of gas tends to decrease.