Sucrose, commonly known as table sugar, is a disaccharide with the chemical formula C12H22O11. The direct answer to whether it conducts electricity when dissolved is no; a sucrose solution does not allow an electric current to pass through it. This non-conductive property holds true for both its crystalline solid form and when it is dissolved in water. The reason lies in the fundamental differences in how compounds hold their atoms together and how electricity moves through a substance.
How Electricity Moves Through Substances
Electrical current is defined as the net flow of charged particles through a material. For any substance to conduct electricity, it must contain charge carriers that are free to move. These mobile charge carriers fall into two main categories depending on the type of conductor.
In solid metals, conduction occurs through a “sea” of delocalized electrons that are not bound to any single atom. These electrons are highly mobile and can flow easily when a voltage is applied.
In liquid solutions, however, the charge carriers must be free-moving ions, which are atoms or molecules that carry a net positive or negative charge. The flow of current in a solution, known as electrolytic conduction, requires these charged ions to physically migrate toward electrodes of the opposite charge. Without an abundance of such mobile, charged particles, the solution acts as an insulator, effectively blocking the flow of electricity.
The Molecular Structure of Sucrose
Sucrose is classified as a molecular compound, meaning its atoms are held together by strong covalent bonds. These bonds are formed by the sharing of electrons between the carbon, hydrogen, and oxygen atoms in the molecule. The sharing of electrons results in a single, large, electrically neutral molecule (C12H22O11).
Since the electrons are shared within the covalent bonds, they are localized and not free to move throughout the structure. Furthermore, the entire C12H22O11 molecule lacks a net electrical charge. This absence of both mobile electrons and pre-existing ions means that solid sucrose cannot carry an electric current.
Dissolving Sucrose vs. Ionizing Salts
When crystalline table sugar is added to water, the water molecules surround and separate the individual sucrose molecules. The molecules disperse throughout the solvent but remain intact as neutral C12H22O11 units.
Because no charged particles are formed, the resulting sugar water lacks the mobile ions necessary to carry a current. Consequently, a sucrose solution is classified as a non-electrolyte. This is a physical change where the molecular structure is preserved.
This mechanism contrasts sharply with what occurs when an ionic compound, such as table salt (sodium chloride, NaCl), is dissolved. Salt is held together by ionic bonds, where electrons are transferred, creating positive sodium ions (Na+) and negative chloride ions (Cl-). When salt dissolves, the water causes the compound to dissociate, or break apart, into these separate, mobile charged ions. These free-moving ions act as the charge carriers, allowing the salt solution to conduct electricity, which is why it is called an electrolyte.