Electrolytes and Non-Electrolytes- An Introduction
Ionic substances are all electrolytes. Ions are formed when ionic substances dissolve, and they can conduct currents when they do so (conductivity). Because they can conduct a current when molten (melted).
A substance is referred to as a nonelectrolyte if it doesn't conduct electricity in either the molten or watery form. Many molecules, including ethanol and sugar, are nonelectrolytes.
Definition of Electrolytes and Non-Electrolytes
A compound that conducts electricity in an aqueous and molten form are known as electrolytes. Electrolytes conduct electricity because of the ions present in the solution. The ionic compounds, when dissociated from each other in a compound, release ions. An aqueous solution of organic acids, bases and salts that do not conduct electricity comes under the category of electrolytes. On the other hand, some compounds which are not able to dissociate are known as non-electrolytes. Aqueous solutions of urea and sugar are examples of non-electrolytes.
Strong Electrolytes
Strong electrolytes have the ability to completely dissociate, due to this characteristic, these compounds or molecules conduct electricity when present in the molten state (solution). These compounds possess lower vapour pressure than other electrolytes because they are dissociated easily. NaCl is one of the most common examples of strong electrolytes as they are frequently used in electrical conductivity and many other experiments.
Weak Electrolytes
Weak electrolytes ionisation capacity is measured by molar concentration and a volume containing one mole of solute present. It is given by the formula
α=���
(V=1/concentration)
Here,
V=volume of one mole of solutes.
Ka = dissociation constant
α = degree of dissociation
Thus, in weak electrolytes, the degree of ionisation is directly proportional to the square root of the volume containing one mole of solutes. This is known as Ostwald's dilution law. This law is given by Wilhelm Ostwald. Acetic acid is the most common example of weak electrolytes.
Difference Between Electrolytes and Non-Electrolytes
Difference Between Strong and Weak Electrolytes
Some Common Electrolytes in Our Body
Sodium - Helps in the transmission of nerve signals and water retention in the body.
Potassium - They're essential for a healthy heart, muscles, kidneys, and nerves.
Magnesium - Maintains blood glucose levels, and healthy heart rate, and acts as a coenzyme for many metabolic reactions inside the body.
Some Examples of Non-Electrolytes
Toluene - Toluene are non-polar in nature. When it is mixed with water, it forms an emulsion. They are often prepared by the use of emulsifying agents and do not dissociate into ions. That is why they are considered non-electrolytes.
Alcohol - Ethyl alcohol is composed of the molecule CH3CH2OH. There are covalent bonds in alcohol. Alcohol and water combine, however, because of the covalent bonding, the alcohol does not disintegrate into ions. Hence, they are termed non-electrolytes.
Uses of Common Non-electrolytes
Insulating Agents - non-electrolytes, because of their non-conducting nature, are used as insulators.
Naphthalene Aalls are examples of non-electrolyte. It changes its state directly from solid to gas.
Chloroform - Chloroform is an unreactive molecule and non-polar in nature.
Key Features of Electrolytes and Non-electrolytes
When electrolytes are dissolved or melted, they allow the flow of electric current.
When melted or in solution, non-electrolytes do not conduct electricity.
The body uses some electrolytes for vital functions.
Non-electrolytes, due to their non-polarizing nature, are used as preservatives, surfactants and insulators.
FAQs on Difference Between Electrolytes and Non-Electrolytes for JEE Main 2026
1. What is the fundamental chemical difference between an electrolyte and a non-electrolyte from a JEE perspective?
The fundamental difference lies in their ability to dissociate into ions. An electrolyte is a compound that, when dissolved in a suitable solvent (like water) or melted, produces mobile ions and can therefore conduct electricity. A non-electrolyte is a compound that dissolves to produce neutral molecules, not ions, and its solution does not conduct electricity.
2. How are strong and weak electrolytes differentiated quantitatively in JEE Main problems?
The key quantitative differentiator is the degree of dissociation (α).
- Strong electrolytes are assumed to dissociate completely, so their α is approximately 1. There is no equilibrium involved. Example: NaCl → Na⁺ + Cl⁻.
- Weak electrolytes dissociate only partially, establishing an ionic equilibrium. Their α is much less than 1 (α << 1), and their dissociation is governed by an equilibrium constant (Kₐ for acids, Kₑ for bases). Example: CH₃COOH ⇌ H⁺ + CH₃COO⁻.
3. How does the presence of electrolytes versus non-electrolytes affect the colligative properties of a solution?
Electrolytes have a more pronounced effect on colligative properties due to dissociation. This is accounted for by the van't Hoff factor (i), which represents the number of particles a solute forms in solution.
- For non-electrolytes (like glucose or urea), i = 1, as they do not dissociate.
- For electrolytes (like NaCl or MgCl₂), i > 1, because they dissociate into multiple ions (e.g., theoretically, i=2 for NaCl and i=3 for MgCl₂).
4. For JEE Main, what is the critical distinction between an 'electrolyte' and an 'electrode'?
This is a common point of confusion. An electrolyte is the substance (compound or solution) containing free-moving ions that conducts electricity through ionic movement. An electrode is the solid electrical conductor (usually a metal or graphite rod) through which the electric current enters or leaves the electrolyte during electrolysis or in an electrochemical cell.
5. Why do ionic compounds like NaCl dissolve in water but not in a non-polar solvent like benzene?
This is explained by the principle 'like dissolves like'. Water is a polar solvent with a high dielectric constant. It can surround the Na⁺ and Cl⁻ ions, a process called hydration, releasing sufficient energy (hydration enthalpy) to overcome the lattice enthalpy of the NaCl crystal. Benzene is a non-polar solvent and cannot effectively solvate the ions, so it is unable to break the strong electrostatic forces holding the ionic lattice together.
6. How does dilution impact the molar conductivity of strong and weak electrolytes differently?
The impact of dilution on molar conductivity (Λₘ) is a key concept for JEE.
- For a strong electrolyte, molar conductivity increases gradually with dilution. This is because dilution decreases the inter-ionic forces of attraction, allowing ions to move more freely.
- For a weak electrolyte, molar conductivity increases sharply with dilution. According to Ostwald's dilution law, dilution increases the degree of dissociation (α), significantly raising the number of current-carrying ions in the solution, which causes a sharp rise in Λₘ.
7. Why are compounds like sugar (sucrose) and ethyl alcohol considered non-electrolytes despite being highly soluble in water?
Sugar and ethyl alcohol are covalent compounds. Although they are soluble in water due to hydrogen bonding between their molecules and water molecules, they do not ionise. The covalent bonds within their molecules remain intact upon dissolution. Since they only disperse as neutral molecules and do not produce any free-moving ions, their aqueous solutions are unable to conduct electricity, classifying them as non-electrolytes.
