Why Sugar Dissolves in Water?

Water dissolves sugar easily like many other amorphous compounds such as table salt. Sugar molecules, when exposed to water, easily fall apart under the attraction of water molecules just as a magnet would do to iron fillings sprinkled on a plane surface. The mutual force of attraction between the molecules of the two substances is due to the presence of opposite charge and the pull is electric in nature.

A sugar molecule has a hydroxyl group attached to it that has a partial negative charge on it in contrast with partial positive bar on oxygen of water molecule when come in contact, form a bond that servers as a shield to protect it from rest of the sugar molecules. The shield extends through and through and helps avoid any sugar form crystals.

Sugar Why Sugar Dissolves in Water?

Why Sugar Does Not Dissolve Completely?

At times sugar does not dissolve thoroughly. The most obvious reason is low rate of stirring. Other may be temperature — the more heat energy is supplied, the higher will be the rate of dissolution.

In order to ensure a complete dissolution, the solution has to be continuously stirred. The molecules in the container undergo a fluid kinetic motion and keep colliding with each other. This spontaneous collision between water and sugar molecules results in the breaking of sugar molecule and formation of bonds between water and sugar molecules. The water molecules therefore spread apart to accommodate sugar molecules.

The rate of dissolution decreases if the solution is not attended by a continuous stirring. Although at the compromise of time, it will turn into a homogenous mixture even if there is no stirring at all because of the continuous kinetic motion of water molecules.

Heating speeds up the dissolution:

The second law of thermodynamics states that supply of heat energy to an (isolated) system, such as a sugar solution, will increase the kinetic energy, hence greater movement, increased probability of mutual collision and consequently quicker bonding between sugar and water molecules, i.e. the increased rate of dissolution. Another advantage of heat is that water molecules quickly expand and make room for the sugar molecules.

Different Sugars

Other than sucrose, the table sugar, glucose and fructose are also sister sugars. They are water soluble at a quick rate. Upon heating they quicken their rate of dissolution, just like sugar.

A comparative study of salt?

Upon heating salt starts dissolving at a faster rate, a phenomenon commonly encountered during day to day cooking. Gases, however, go the other way round. This is probably the reason that drinks taste well when kept in cold places, because the carbonated fluid keeps its gaseous element intact when cool, but upon heating the gas leaves the mixture — a state characterized by loss of homogeneity. With the result liquid loses its characteristic effervescence and taste as well because of prolonged exposure to either sun or hot environment.

Why does Salt Conduct Electricity and Sugar Does Not?

Salt ionizes in water; ions are the charged particles that float in water. The ion movement conducts electricity and the solution is, therefore, termed as electrolyte. On the contrary, sugar is not ionized; it rather exhibits covalent bonding and hence is not an electrolyte.

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