Conductance of Electrolytic Solutions

In junior classes, you have already learnt about conductors and insulators. However, those were simply the basics of what we’ll learn today. Before we tell you about conductance of electrolytic solutions, let’s understand the term conductor and the types of conductors.

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Conductors and Insulators

Any substance or material, which permits the passage of electricity through it, can be termed as a conductor. On the other hand, any substance which resists the flow of electricity through it is termed as an insulator. Owing to such specific properties of various materials, which may allow or resist the flow of electricity through them, humans have been able to create many lighting and mechanical solutions that are propelled by converted electricity.

Had it not been for the nature of conductors, we would probably still be searching for a medium to harness the electricity available to us.

Types of Conductors

Generally, science divides conductors into two broad categories. The division of conductors or conductance is based on the decomposition of electricity when it passes through a given conductor. Based on the nature of decomposition, conductors could be classified into the following two categories:

Electronic Conductors

An electronic conductor allows the flow of electricity without causing any decomposition of the substance. The most common examples of electronic conductors are metals, graphite and minerals. The flow of electricity in such conductors happens due to the flow of electrons within the substance through which the electricity is made to pass. Also, as the temperature of the substance increases, there is a considerable decrease in the flow of conduction.

Electrolytic conductors

As opposed to the former, the substance undergoes decomposition in the case of electrolytic conduction. Also, the flow of electricity through such conductors happens due to the movement of ions. As the temperature of the substance increases so does the rate of conduction. Examples of such conductors are acids, bases, fused salts and more. The types of Electrolytic conductors are:

• Strong Electrolytic conductors
• Weak Electrolytic conductors.

Strong Electrolytic conductors

If we talk about strong Electrolytic conductors, we would be referring to strong acids and bases such as hydrochloric acid, hydrogen nitrate, sulphur dioxide, potassium iodide and more. Also included in this category would be most of the inorganic salts. The reason why they are referred as strong Electrolytic conductors is that in the aqueous state and molten state, these substances disassociate completely. Hence, they are capable of conducting electricity to a large extent.

Weak Electrolytic conductors

On the other hand, weak Electrolytic conductors include weak acids and bases which have a very low level of disassociation, which is why they conduct electricity only to a small extent. There are some substances, such as sugar and urea, which are not capable of conducting electricity at all, which is why they are referred as non-electrolytes or non-Electrolytic conductors.

Factors affecting Electrolytic conduction

Following factors affect the level of Electrolytic conduction:

• Nature of the electrolyte: The strength and composition of a substance largely impact the degree of conduction that can take place through the substance.
• Size of the ion produced and their salvation: The size of an ion within a substance also impacts the degree of disassociation that takes place in a substance. Hence, salvation properties impact their conduction.
• Nature of the solvent and its viscosity: The nature of a solvent and its density also impacts the ability of the substance to allow conduction through it.
• Concentration of the solution: The density and strength of a solution cast an impact on the conduction properties of a substance.
• Temperature: Conduction is highly susceptible to increase or decrease under the influence of the temperature of a given substance. On the other hand, conduction in metallic and electronic substance is affected by the nature and type of the metal, the number of valence electrons per atom and the temperature of the substance.

Rules of Electrolytic Conduction

In a given electrolytic solution, conductivity tends to increase with the decrease in the distance between two electrodes. Conductivity also tends to increase with an increase in the surface distance between the electrodes. Analytes concentration increases the conductivity of an electrolytic solution. Electrolyte nature changes the conductivity in an electrolytic solution.

Solved Examples for You

Question: How does the presence of strong or weak electrolytes affect the degree of increase in conductance?

Answer: As the level of dilution of an electrolytic solution increases, the number of ions present in the solution can be assumed to be greater, which is why their mobility to the electrodes is also considered to be higher. Thus, the degree of conduction in such solution will be higher. On the other hand, a concentrated solution would present a lower chance for ions to mobilize around the electrolytes. Conclusively, conduction would not be as high as in the case of a diluted solution. Thus, the number of ions present in a solution is highly indicative of the conductance of a given solution.