why organic compound freezes from bottom while water freezes from top???
The reason why organic compounds freeze from the bottom up while water freezes from the top down lies in their molecular structures and the properties of their solid forms.
Water molecules have a unique arrangement and hydrogen bonding that allows them to form a crystalline lattice structure in the solid state, also known as ice. As water cools and approaches its freezing point, the hydrogen bonds between water molecules become stronger, causing the molecules to arrange themselves in a more ordered manner. This structure forms an open framework where the water molecules form hexagonal patterns, leaving empty spaces or "holes" between the molecules. These hexagonal spaces are less dense than the surrounding water molecules, causing the ice to float on top of the liquid water.
On the other hand, organic compounds typically do not form the same kind of hydrogen bonding as water and lack the ability to create a similar open lattice structure. Rather, the molecules in organic compounds tend to pack more densely when they solidify. As the temperature decreases, the individual molecules become less mobile and start to arrange themselves in a more ordered arrangement.
Since the molecules in organic compounds are denser in their solid form, they sink and settle at the bottom as the solidification process progresses. The freezing starts from the bottom and gradually propagates upward. This is different from water, where the less dense, crystalline structure of ice forms at the top and expands downward, displacing the liquid water.
To understand why a particular substance freezes in a specific way, it is essential to study its molecular properties, intermolecular forces, and how these factors influence its solidification process.