Variations of Molar Conductivity

Conductivity of an electrolytic solution at a specific concentration, also known as specific conductivity of an electrolytic solution, is the conductance produced by a unit volume of solution held between two platinum electrodes separated by a unit length and with a unit cross-section, both of which are platinum. A solution’s conductivity decreases with dilution because the number of ions per unit volume that are capable of carrying current in a solution decreases with dilution. It is known as conductivity when a solution has the ability to transfer current between its atoms. The Greek letter kappa is used to denote this phenomenon (k).

Here are a few examples of variables that can have an impact on electrical conductivity:

It is a very sensitive physical quantity that is influenced by a wide variety of factors…. The following are a few of these considerations.

• The chemical composition of an electrolyte is important.
• It is measured in millimeters for ions when it comes to their molecular mass.
• The strength of a solution’s concentration is expressed as a percentage of its total concentration.
• Temperature
• The chemical composition of the solvent.

Limiting Molar Conductivity

It is known as limiting molar conductivity when the molar conductivity of a solution is constant at infinite dilution. With another way of putting it: as soon as the concentration of the electrolyte approaches zero, the molar conductivity is known as limiting molar conductance.

Molar Conductivity

The conductance of volume V of a solution containing one mole of electrolyte kept between two electrodes with an area of cross-section A and a distance of unit length is defined as the molar conductivity of a solution at a given concentration.

Ʌm = К/c

Here,

c = concentration in moles in per volume of the solution

К = specific conductivity

Ʌm = molar conductivity.

As the solution contains only one mole of electrolyte, the above equation can be modified as below one:

Ʌm =К *V

As concentration is decreased, conductivity in solutions decreases because the number of ions per unit volume that can hold the current in a solution decreases with dilution, whereas the molar conductivity of a solution increases as concentration is decreased. The increase in molar conductivity is due to the increase in the total volume containing one mole of the electrolyte as a result of the increase in total volume.

Variation in the molar conductivity

With concentration for electrolytes that are potent:

The molar conductance of strong electrolytes increases slowly with dilution because of the high concentration of the electrolyte. The relationship between molar conductivity and c1/2 is represented by a straight line with a y-intercept equal to °m. The value of limiting molar conductivity, °m, can be calculated from the graph or with the help of Kohlrausch’s law of conductivity. The generic equation for the plot is denoted by the notation:

The molar conductance of strong electrolytes increases slowly with dilution because of the high concentration of the electrolyte. The relationship between molar conductivity and c1/2 is represented by a straight line with a y-intercept equal to °m. The value of limiting molar conductivity, °m, can be calculated from the graph or with the help of Kohlrausch’s law of conductivity. The generic equation for the plot is denoted by the notation:

Ʌm = Ë°m -Ac ^1/2

Where A is a constant equal to the slope of the line and -A is the slope of the line. In the case of a given solvent, the value of “A” is determined by the type of electrolyte present at a specific temperature.

With concentration for weak electrolyte:

Unlike for strong electrolytes, the graph shown between molar conductivity and half-concentration (where c is the concentration) is not a straight line in the case of weak electrolytes. The molar conductivities and degree of dissociation of weak electrolytes are lower at greater concentrations, while the degree of dissociation increases abruptly at lower concentrations. In the absence of zero concentration, it is impossible to determine the limiting molar conductivity, m°, by extrapolating the molar conductivity to zero concentration. As a result, we employ the Kohlrausch law of independent migration of ions to determine the molar conductivity, m°, of weak electrolytes in order to determine their limit molar conductivity.

The presence of free ions in electrolytes leads them to conduct electricity due to their ability to conduct electricity. It’s similar to the way free electrons promote the conduction of electricity in metallic conductors, which is equivalent. When it comes to electrolytic conduction, the Arrhenius equation or principle is utilised to describe it.

We’re all aware of electrolytic solutions, which are created by dissolving a variety of salts in a solution. It is not necessary for the salts to be ionic all of the time. The only prerequisite is that the compound be composed of ions with diametrically opposed charges.

After dissolving an electrolyte in water, the Arrhenius principle states that the electrolyte molecules will be separated into two distinct charged ions, each with a different charge.

What Is the Difference Between Strong Electrolytes and Weak Electrolytes?

When strong and weak electrolytes react together, they do not entirely dissociate into the solvent, whereas weak electrolytes can totally dissolve in aqueous solution. Molecular constituents of the solution, as well as the ions present in the electrolyte, are present. Weak electrolytes only partially ionize in water, whereas strong electrolytes completely ionise in water. Weak electrolytes are defined as bases and acids that are too weak to dissolve in water. Strong electrolytes are those that contain strong bases, strong acids, and strong salts. Salt is regarded a powerful electrolyte despite the fact that it has a poor solubility in water. This is due to the fact that whatever quantity of salt dissolves in water is totally ionized.

Examples of weak electrolytes include: Acetic acid (CH₃COOH) is a kind of organic acid. Acetic acid is the acid present in vinegar, and it is a weak acid. It is an electrolyte that is particularly soluble in water and is used as a diuretic. But when it is dissolved in the water, most of its original molecule remains as it is, instead of being in the ion form. Ethanoate is the name given to this primordial form. The acetic acid is dissolved in water and ionizes to form ethanoate and the hydronium ion, which are both toxic. As a result, acetic acid is considered a weak electrolyte.

Conclusion

The presence of free ions in electrolytes leads them to conduct electricity due to their ability to conduct electricity. It’s similar to the way free electrons promote the conduction of electricity in metallic conductors, which is equivalent. When it comes to electrolytic conduction, the Arrhenius equation or principle is used to describe it.

We’re all aware of electrolytic solutions, which are created by dissolving a variety of salts in a solution. It is not necessary for the salts to be ionic all of the time. The only prerequisite is that the compound be composed of ions with diametrically opposed charges.

After dissolving an electrolyte in water, the Arrhenius principle states that the electrolyte molecules will be separated into two distinct charged ions, each with a different charge.

The charged particles have complete freedom to move about in the solution. Positive ions, also known as cations, may migrate towards a negative electrode, also known as a cathode, in order to lessen their own charge. Positive ions or anions will go toward the positive electrode or anode and oxidize themselves at the same time. Electric conduction is caused by the passage of charged particles across a fluid medium.