https://van.physics.illinois.edu/ask/listing/1457
What is the boiling and freezing point of both fresh and saltwater?
- maria (age 13)
congress middle, lake worth , F.L., Florida
A:
Hi Maria,
For pure water, the boiling point is 100 degrees Celsius (212 Fahrenheit) at one atmosphere of pressure, and the melting point is 0 degrees Celsius (32 degrees Fahrenheit) at one atmosphere of pressure. At at high altitudes the lower pressure makes the boiling point several degrees lower. For example, in Denver, Colorado, the boiling point is about 95°C or 203°F.
For saltwater, the boiling point is raised, and the melting point is lowered. By how much depends on how much salt there is. I’ll assume the salt is sodium chloride, NaCl (table salt). The melting point is lowered by 1.85 degrees Celsius if 29.2 grams of salt are dissolved in each Kg of water (called a “0.5 molal solution” of salt. The Na and Cl dissociate right away when dissolved, and so for a 0.5 molal solution of salt, there is a 1.0 molal concentration of ions). The boiling point is raised by 0.5 degrees Celsius for water with 29.2 grams of salt dissolved in each kg of water.
If your concentrations of salt are different, then you can scale the boiling point elevation and melting point depression predictions directly with the concentration.
These numbers come from the CRC Handbook of Chemistry and Physics.
Tom
Boiling seas is beyond fictional and not even pseudoscience.