Question

Harry: Hey Hermione, does a supersaturated solution made by increasing temperature stay like that forever when left idle in a room?
Hermione gave him a blank look thinking Harry was an idiot.

Why did Hermione think Harry was an idiot?

• A. Because supersaturated solutions stay forever once made.
• B. Because a solution can never be supersaturated. It is an idealistic phenomenon.
• C. Because a supersaturated solution can be formed for a limited time only.
• D. Because all solutions are supersaturated.

Answer 1

The correct option is C Because a supersaturated solution can be formed for a limited time only.

Hermione is very intelligent. She knows that supersaturated solutions cannot stay like that because the basis of supersaturation is the time it takes for the solute particles to crystallize.

Solute particles actually take longer to crystallize out after the temperature drops than it takes for the temperature to drop.

For example, if it takes 1 minute for temperature to reach 25 C from 35 C, it would take 2 minutes for the solute particles to form crystals and separate out. In that 1 min duration, we say the solution is supersaturated.