What are the factors that affect the electrical conductivity of solutions of ionic compounds?

Answered by Phillip Nicastro

There are several factors that can affect the electrical conductivity of solutions of ionic compounds. These factors include the concentration of dissolved ions, the type of ions present, and the temperature of the solution.

1) Concentration of dissolved ions: The conductivity of a solution depends on the number of ions present in the solution. Higher concentrations of ions will result in higher conductivity, as there are more charged particles available to carry the electrical current. Conversely, lower concentrations of ions will result in lower conductivity.

To illustrate this, let’s consider a simple example. Suppose we have two beakers of water, one containing a high concentration of sodium chloride (NaCl) and the other containing a low concentration of NaCl. When an electric current is passed through the solutions, the beaker with the higher concentration of NaCl will exhibit a higher conductivity, as there are more ions available to carry the current.

2) Type of ions: The nature of the ions present in a solution also affects its conductivity. Some ions carry higher charges than others, and ions with higher charges tend to have higher conductivities. For example, a solution containing highly charged ions such as Ca2+ and Cl- will generally have higher conductivity compared to a solution containing singly charged ions such as Na+ and Cl-.

Furthermore, the size of the ions can also influence conductivity. Smaller ions tend to have higher conductivities compared to larger ions. This is because smaller ions can move more easily through the solution, enabling a higher conductivity. For instance, in a solution of potassium chloride (KCl) and sodium chloride (NaCl), the K+ ions are smaller than Na+ ions, and thus the KCl solution will have a higher conductivity.

3) Temperature: The temperature of the solution can also impact its conductivity. Generally, as the temperature increases, the conductivity of the solution also increases. This is because higher temperatures provide more energy to the ions, allowing them to move more freely and carry the electrical current more effectively.

However, this relationship between temperature and conductivity is not always linear. In some cases, at very high temperatures, the conductivity may start to decrease due to other factors such as the dissociation of water molecules. It is important to note that the effect of temperature on conductivity can vary depending on the specific ions and their chemical properties.

The conductivity of solutions of ionic compounds is influenced by the concentration of dissolved ions, the type of ions present, and the temperature of the solution. Higher concentrations of ions, ions with higher charges, and smaller ions tend to result in higher conductivity. Additionally, an increase in temperature generally leads to increased conductivity, although the relationship can be complex.