ANS:A - reduce the capacity

In a multiple effect evaporator, the effect of boiling point elevation refers to the increase in the boiling point of the solution due to the presence of solutes. This phenomenon can affect the overall performance of the evaporator system. Boiling point elevation typically results in an increase in the temperature required to evaporate the solvent from the solution. As a result:

• It reduces the capacity: The increased boiling point means that more heat is required to achieve evaporation, which can reduce the overall capacity of the evaporator system to process a given amount of solution.
• It reduces the economy: Since more energy is required to achieve evaporation due to boiling point elevation, the energy efficiency or economy of the evaporator system is reduced. This means that more energy input is needed to produce the same amount of concentrated product.