Freezing Point Depression

Freezing Point Depression Explained

Freezing point depression is a phenomenon of takes place when the freezing point of a fluid, i.e. a solvent, is lowered (depressed) by the addition of another compound or a solute. The addition gives a solution that has its freezing temperature at a lower point than that of the pure original solvent. This results in re-establishment of the equilibrium between the liquid and solid phase at another temperature altogether, i.e. depression of freezing point. This happens every time a solute is included to a solvent like water. A good daily life example of freezing point depression can be seen in sea water. Sea water has a tendency to remain liquid even below temperatures of 0 ⁰C which is the freezing point of uncontaminated water. This happens due to the water’s salt content.

Freezing point depression - Uses in Practical Life

Freezing point depression and its occurrence has application in industrial as well as personal sectors. It is most often used in technological relevance where freezing is to be prevented.

Freezing Point Depression

A good example here is water. Ethylene glycol or any other anti-freeze solute is put in to the cooling water in modern IC (Internal Combustion) engines. This addition makes sure the mixture of cooling water and ethylene glycol stays liquid even well beneath its average freezing point. Another place where this phenomenon finds use is in the cooling of beverages and beers positioned in an ice bath which contains salt.

Freezing point depression - Used in Preventing Black Ice Formation

Freezing point depression has also another useful application. Black ice is the thin coating of ice on a surface, more specifically on a road surface. Also known as glare ice or clear ice, it is very dangerous to drive on and most often forms on roads. It is totally transparent which allows the black color of the asphalt to come through. This gives the name black ice. Because of this, drivers do not get a good judgement of the ice patches which can cause imbalance and ultimately even lead to accidents. With the help of road salting, the ice or snow melts and remains in liquid state due to the effect of freezing point depression.

Freezing point depression - Used by many Animals

Freezing point depression phenomena also influence some animals living in very cold conditions that use “freeze avoidance” techniques. The animals find an increase in the concentration of inert substances like glycerol and sorbitol in their blood. What this increase does is preventing the freezing of fluids in tissues and cells and thereby keeping them motile. Many species of Arctic habituating fishes like the rainbow smelt and the spring peeper frog are prominent examples of such animals. For the spring peeper frog, this is done by the liver’s breaking down of glycogen which subsequently releases huge amounts of glucose.

Freezing point depression is analogous to the observable fact of boiling point increase. But the difference is that the freezing point depression has a larger magnitude than the boiling point increase for the similar solvent and concentration. Basically this increases the fluid assortment of a solvent in the existence of a solute. this is what is meant by Freezing point depression.