Question

Why doesn’t sea water freeze so easily?

Answer 1

Hint: To solve this question, we must first understand the constituents of a sample of sea water and a water of pure water. Then we need to discuss the effects of the substituents present in sea water that affect the freezing point of water.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Freezing point of any liquid can be understood as the temperature at which the given liquid transforms from its liquid state to its solid state. This can be better explained by understanding the molecular energy of a given substance. Temperature is a direct translation of the energy of the system. So, if we decrease the energy of a system to a considerable extent, then we can change the state of matter of the substance.
The major solute particle present in seawater is salt. And we know that salt particles dissociate when placed in an aqueous solution. So, the number of solute particles increases to a large extent in comparison to a sample of fresh water which contains no other solute particles. Being a colligative property, the freezing point of water decreases with the increase in the number of solute particles.
Because of this reason, the freezing point of sea water is lower than that of regular water, and hence, sea water does not freeze easily.

Note: Colligative properties of a substance can be explained as those characteristics of a solution that depend on the number of the solute particles present in the solution. Freezing point of a liquid is also a colligative property; hence it depends on the solute particles of the solution.