Introduction 

The electrolyte ions that are most effective in causing coagulation are those that have a charge that is the polar opposite of that of the colloidal particles. Coagulating ions are the name given to these ions. It is believed that the higher the valency of the coagulating or Flocculating ion, the greater its ability to bring about coagulation is.

The ability to cause precipitation increases as the following elements are added: Al3+>Ba2>Na+

The coagulation capacity of dissimilar electrolytes varies depending on the valency of the active ion, also known as a flocculating ion, present in the solution (carrying a charge opposite to the charge of the colloidal particles).

Explanation

Coagulating ions are those ions that are responsible for causing the coagulation of colloidal solutions. Ions are unstable, and the greater the valency of an ion, the greater the ionic volatility. Therefore, negative ions cause the precipitation of positively charged sols while positive ions precipitate the precipitation of negatively charged sols. According to the Hardy-Schulze rule, the coagulation capability of an electrolyte varies in proportion to the variation in the valence ions present in it. Consequently, when the valency of the active ion is increased, the coagulating power of the ion will also increase in proportion.

In most cases, coagulation occurs as a result of the accumulation of electrolytes in the bloodstream. In the presence of an electrolyte, the particles of a colloidal solution are neutralised by the particles of an electrolyte that have opposite charges to the particles of the colloidal solution. The neutral particles then begin to accumulate and combine to form larger-scale particles, which eventually settle as a precipitate on the surface of the water.

Colloidal solutions are purified through a process known as chromatography.

According to the Hardy-Schulze rule, the greater the valency of the active ion or flocculating ion, the greater the coagulating power of the active ion or flocculating ion. It is dependent on the valency of the active ion, which is the ion carrying a charge that is opposite to the charge of the colloidal particles, and is referred to as the flocculating ion.

Coagulation is caused by ions that have a charge that is diametrically opposed to that of the sol. In this way, a Fe(OH)3 sol that is positively charged is coagulated by negatively charged ions such as Cl–,SO42-, and so on. Similarly, arsenic sulphide sol, which has a negative charge, is coagulated by positive ions, which are attracted to it. So the coagulating power of iron increases as the valency of the active ion increases in a proportional manner.

Limitation

However, the charge carried by an ion, rather than its size, is taken into consideration by this law in this case. The smaller the size of an ion, the greater the amount of polarising control it will have. 

Consequently, the Hardy-Schulze law can be modified in terms of the polarising power of the flocculating ion used in the flocculation process. So the modified Hardy-Schulze law can be stated as follows: ‘the greater the polarising power of the flocculating ion added, the greater is its ability to cause precipitation.’

The Hardy-Schulze rule can be used to estimate the amount of electrolyte required to coagulate a colloidal solution in a given situation. Hardy and Schulze made this observation, and it became a rule.

According to the Hardy Schulze rule, the amount of electrolyte required to cause colloidal solution to coagulate a specific amount of colloidal solution is dependent on the charge of the coagulating ion. (A coagulating ion is an ion that has a charge that is diametrically opposed to the charge of the colloidal particles.)

Cooperation is the process of colloidal particles coming together, which results in the formation of larger particles that either settle down as a precipitate or float on the surface of a liquid. In most cases, the addition of electrolytes is responsible for causing coagulation.

A colloid is neutralised by the addition of an electrolyte, which is a substance that attracts ions that have opposite charges to the colloid’s particles and thus neutralises the colloid. The neutralised particles accumulate and combine to form larger particles, which eventually settle to the bottom of the container.

The ions in the electrolyte that cause the colloid to coagulate are referred to as flocculating or coagulating ions, depending on their function. Hardy and Schulze discovered that the higher the valency of the flocculating ion or coagulating ion, the greater the power of the ion to coagulate. 

Additionally, the coagulation or flocculation value of an electrolyte is defined as the minimum amount of an electrolyte that must be added to one litre of a colloidal solution in order to bring about complete coagulation or flocculation.

As a result, the lower the flocculation value of an electrolyte, the greater the coagulating or precipitating power of the electrolyte.

As an illustration,PO43 coagulates a positive sol more effectively than Cl because the valency of (-3) is numerically greater than that of (-2). (-1).

Conclusion

In order to bring about coagulation, the effective ions of the electrolyte, which are those that carry a charge that is opposite to that of colloidal particles, are necessary. The effective ions of the electrolyte are those that carry a charge that is opposite to that of colloidal particles. These ions are referred to as coagulating ions or fluctuating ions in some circles. The greater the valency of coagulating or fluctuating ions, the greater the power of the ions to cause coagulation to occur.