Question

The ratio of the colligative effect produced by an electrolyte solution to the corresponding effect for the same concentration of a non-electrolyte solution is known as (a) degree of dissociation (b) degree of association (c) activity coefficient (d) van't Hoff factor

Short answer

The correct answer is (d) van't Hoff factor.

Step-by-step solution

Identification

It's important to identify the different options presented and understand their definition.

Recalling definitions

The degree of dissociation refers to the extent to which a compound separates into its constituents(i.e., ions). Degree of association refers to the extent to which particles form aggregated groups in a solution. Activity coefficient is a measure of the deviation from the ideal behavior of a solution. Van't Hoff factor, denoted as 'i', is the ratio of actual concentration of particles produced when a substance is dissolved, to the concentration of a substance as calculated from its mass.

Matching definition

Based on the definitions and understanding, the term asked in the question refers to Van't Hoff factor which is used to measure the colligative properties of electrolytes and non-electrolyte solutions.

Key concepts

Van't Hoff Factor

The Van't Hoff factor is a key concept in understanding colligative properties of solutions. It represents the number of particles a solute dissociates into when it dissolves in a solvent. This factor is essential for determining the overall effect of a solute on a solution's colligative properties, such as boiling point elevation, freezing point depression, and osmotic pressure.

The Van't Hoff factor, denoted by the symbol \(i\), can be calculated as follows:

• For non-electrolytes, which do not dissociate, \(i = 1\).
• For electrolytes, \(i\) varies depending on the number of ions produced. For example, NaCl dissociates into two ions (\(Na^+\) and \(Cl^-\)), so \(i = 2\).

This factor helps us predict how the presence of a solute affects a solution's properties by quantifying the number of particles in the solution.

Electrolyte Solution

Electrolyte solutions are solutions that contain solutes which ionize in water, meaning they break apart into ions. These ions are charged particles that can conduct electricity when they are dissolved in a solvent like water.

When an electrolyte dissolves, it dissociates into its individual ions. This is what contributes to the conductivity of the solution. Electrolyte solutions are essential in various chemical and biological processes. Common examples include:

• Sodium chloride (\(NaCl\)
• Potassium chloride (\(KCl\))
• Calcium chloride (\(CaCl_2\))

These solutions are crucial in fields such as chemistry, physiology, and medicine, as they play an important role in maintaining electrical neutrality and fluid balance in the body.

Non-Electrolyte Solution

Non-electrolyte solutions contain solutes that do not dissociate into ions in solution. As a result, these solutions do not conduct electricity. Non-electrolyte solutes usually consist of molecules that remain intact when dissolved in a solvent like water.

Common examples of non-electrolyte solutions include:

• Sugar solutions, where sugar molecules remain whole.
• Alcohol solutions, such as ethanol, which do not ionize.

Unlike electrolyte solutions, non-electrolytes do not contribute to electrical conductivity. However, they still affect other colligative properties, such as the boiling point and freezing point of the solvent.

Degree of Dissociation

The degree of dissociation is a concept used to describe how much a compound has separated into its ions in solution. It is crucial for understanding the behavior of electrolyte solutions. This degree is usually represented by the symbol \(\alpha\), which indicates the fraction of the original molecules that dissociate into ions.

The degree of dissociation is calculated using the formula:

• \(\alpha = \frac{n_d}{n_t}\)

where \(n_d\) is the number of dissociated molecules and \(n_t\) is the total number of molecules initially present.

Several factors can influence the degree of dissociation:

• The nature of the solute.
• The concentration of the solution.
• The temperature of the solution.

A high degree of dissociation means more ions are present, affecting the solution's colligative properties such as conductivity, boiling point, and freezing point.