ANS:B - driving force for the liquid flow is its weight.

Inside distillation columns:

• The highest temperature is near the feed plate: This statement is generally true. The highest temperature in a distillation column typically occurs near the bottom of the column, close to the reboiler. This is because the reboiler provides heat to vaporize the liquid feed, leading to higher temperatures in the lower sections of the column.
• The driving force for the liquid flow is its weight: This statement is true. In a distillation column, gravity acts as the primary driving force for liquid flow. As liquid flows downward due to gravity, it encounters trays or packing where vapor-liquid contact occurs, facilitating the separation of components based on their relative volatilities.
• Vapors are not always at their dew points: This statement is also true. Vapors in a distillation column may not always be at their dew points. The dew point is the temperature at which a vapor starts to condense into a liquid at a given pressure. In a distillation column, vapor and liquid phases are in equilibrium, but deviations from equilibrium can occur due to factors such as non-ideal behavior, tray or packing efficiency, and temperature variations along the column. As a result, vapors in a distillation column may be at temperatures above or below their dew points.