Question

Why does coconut oil thicken in winter?

Answer 1

As we know coconut oil is a fatty acid. It consists of two kinds of fatty acids- (i) Saturated fats (ii) Unsaturated fats. The proportion of Saturated fats is $90\%$ and that of Unsaturated fats is $10\%$. Coconut oil solidifies when the temperature of the surrounding falls below room temperature.

Complete answer:
Coconut oil majorly consists of saturated fatty acids. The saturated fatty acids tend to solidify at lower temperatures. Saturated compounds contain long hydrocarbon chains which have hydrogen atoms. These hydrogen atoms form bonds with other molecules via van-der-Waals forces. So the molecules come together and It seems like the substance is a solid. To overcome this force of attraction, more heat has to be applied to melt it. This is why coconut oil has to be heated in winter to make it liquid again.
In the case of compounds with more quantity of unsaturated fatty acids, the hydrocarbon chain has some bends which do not bring it together. So the unsaturated fats have fewer van-der-Waals forces. They are particularly liquid at room temperature and do not solidify at low temperatures. For example, Soybean oil, groundnut oil doesn’t change phase at low temperature.
Therefore, coconut oil solidifies in winter because of more percent of saturated fatty acids.

Note:
A Substance remains in the liquid state when it has more unsaturated content. Also, the more double bonds less is the degree of the melting point of the substance. Saturated fatty acids (Coconut oil) have a higher melting point than unsaturated fatty acids (Vegetable oil).