Question

Yasmin's teacher asks her to make a supersaturated saline solution. Her teacher tells her that the solubility of the salt is 360 g/L at room temperature (25 °C).
How can Yasmin make a supersaturated saline solution?


She can add 380 g of salt to 1 L of hot water (75 °C) and stir until all the salt dissolves. Then, she can carefully cool the solution to room temperature (25 °C).

She can add 360 g of salt to 1 L of room temperature water (25 °C) and stir the solution until all the salt dissolves.

She can add 380 g of salt to 1 L of cold water (5 °C) and stir the solution until most of the salt dissolves. Then, she can carefully heat the solution to room temperature (25 °C).

She can add 380 g of salt to 1 L of room temperature water (25 °C) and let the solution sit for 24 hours, so the salt dissolves.

Answer 1

B just took test and got the correct answer.

Answer 2

Answer:

She can add 380 g of salt to 1 L of hot water (75 °C) and stir until all the salt dissolves. Then, she can carefully cool the solution to room temperature.  

Explanation:

A supersaturated solution contains more salt than it can normally hold at a given temperature.

A saturated solution at 25 °C contains 360 g of salt per litre, and water at 70 °C can hold more salt.

Yasmin can dissolve 380 g of salt in 1 L of water at 70 °C. Then she can carefully cool the solution to 25 °C, and she will have a supersaturated solution.

B and D are wrong. The most salt that will dissolve at 25 °C is 360 g. She will have a saturated solution.

C is wrong. Only 356 g of salt will dissolve at 5 °C, so that's what Yasmin will have in her solution at 25 °C. She will have a dilute solution.