Answer – The Van’t Hoff factor is a dimensionless parameter used to describe the extent of dissociation or association of solute particles in a given solution. It is denoted by “i.”

Explanation: 

Also known as the Van’t Hoff coefficient, this factor is named after the Dutch chemist Jacobus Henricus Van’t Hoff, who discovered it in 1886. It is calculated using the formula

i = 𝝰n + (1 – 𝝰 ),

where i = Van’t Hoff factor, 𝝰 = degree of dissociation, and n = the number of ions formed from one formula unit of the substance.

The Van’t Hoff factor helps to understand the degree of dissociation or ionization of solute species. It provides insights into the behavior of solutes in solutions. In ideal solutions, there’s no association or dissociation of solutes. Therefore, the factor here is equal to 1. When ethanol dissolves in water, it does not dissociate into ions or undergo any association in the solution i.e., C₂H₅OH (l) → C₂H₅OH (aq). Thus, the Van’t Hoff factor is 1 (i = 1). 

For strong electrolytes such as NaCl, the factor is more than 1 (i.e., i > 1). This is because when NaCl dissolves in water, it dissociates into its constituent ions: sodium cations (Na⁺) and chloride anions (Cl^–). This dissociation leads to an increase in the number of solute particles in the solution. For weak electrolytes, there’s no complete dissociation of ions. Therefore, the Van’t Hoff factor is not directly proportional to the number of ions formed and is mostly less than 1 (i < 1).

The Van’t Hoff factor is an essential concept in chemistry, particularly regarding its impact on colligative properties such as boiling points and osmotic pressure. It plays a vital role in various fields like biochemistry, environmental science, and material science.

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