question_answer 1)

  Which of the following changes decrease the vapour pressure of water kept in a sealed vessel? (a) Decreasing the quantity of water                       (b) Adding salt to water (c) Decreasing the volume of the vessel to one-half (d) Decreasing the temperature of water

Answer:

  (b, d) On adding salt to water, its rate of evaporation and vapour pressure both decreases. Similarly, on lowering the temperature, rate of evaporation and vapour pressure decreases.