Question

The vapor pressure of the deliquescent substance is:
A. Equal to the atmospheric pressure
B. Equal to that of the water vapor in air
C. Greater than that of the water vapor in air
D. Less than that of the water vapor in air

Answer 1

A deliquescent substance or compound is a type of material that freely absorbs water from the air. These types of substances absorb water continuously until they dissolve totally in the absorbed water. This process of absorbing water from air is called deliquescence.

Complete step by step answer:
- All the salts which are soluble in water are the best examples of the deliquescent substances.
- Few examples for deliquescent substances are calcium chloride, potassium oxide, sodium nitrate and aluminum chloride.
- To absorb water from air means for deliquescence there should be sufficient amount of humidity in the air.
- One more condition for the process of deliquescence is vapor pressure of the air should be exceeding the vapor pressure of the deliquescent substance.
- Means the vapor pressure of the deliquescent substance is less than that of the water vapor in air. Then only the deliquescence process occurs.
- So, the correct option is D.
Additional information:
- Now a day’s packets comprising deliquescent substances are utilized as desiccants to make other substances dry.
- Deliquescent substances also play a big role in chemical applications like to remove the water liberated during the chemical reactions.

Note: If the vapor pressure of the deliquescent substance is more than the vapor pressure of the water in the air deliquescence process does not occur means the salts won’t absorb water from the air. So, the deliquescent process does not happen in cases where the vapor pressure of the deliquescent substance is very high.