The van t Hoff factor i (named after J. H. van t Hoff) is a meas.pdf

The van \'t Hoff factor i (named after J. H. van \'t Hoff) is a measure of the effect of a solute
upon colligative properties, such as vapor pressure, osmotic pressure and freezing point
depression. The van \'t Hoff factor is the ratio between the actual concentration of particles
produced when the substance is dissolved, and the concentration of a substance as calculated
from its mass. For most non-electrolytes dissolved in water, the van\' t Hoff factor is essentially
1. For most ionic compounds dissolved in water, the van \'t Hoff factor is equal to the number of
discrete ions in a formula unit of the substance. This is true for ideal solutions only, as
occasionally ion pairing occurs in solution. At a given instant a small percentage of the ions are
paired and count as a single particle. Ion pairing occurs to some extent in all electrolyte
solutions. This causes deviation from the van \'t Hoff factor. The deviation for the van \'t Hoff
factor tends to be greatest where the ions have multiple charges.
Relationship with the dissociation degree
The dissociation degree is the fraction of original solute molecules that have dissociated. It is
usually indicated by the Greek symbol . There is a simple relationship between this parameter
and the van \'t Hoff factor. If the solute substance dissociates into n ions, then
i = 1 + (n 1)
For instance, for the following dissociation
KCl K+ + Cl-
As n = 2, we would have that i = 1 +
Physical significance of i
When solute particles associate in solution, i is less than 1. (e.g. ethanoic acid in benzene,
benzoic acid in benzene)
When solute particles dissociate in solution, i is greater than 1. (e.g. sodium chloride in water,
potassium chloride in water, magnesium chloride in water)
When solute particles neither dissociate nor associate in solution, i equals 1. (e.g. Glucose in
water)
The value of i is ; i = the actual number of particles in solution after dissociation ÷ the number
of formula units initially dissolved in solution. Means the number of particles per formula unit of
the solute when a solution is dilute.
Solution
The van \'t Hoff factor i (named after J. H. van \'t Hoff) is a measure of the effect of a solute
upon colligative properties, such as vapor pressure, osmotic pressure and freezing point
depression. The van \'t Hoff factor is the ratio between the actual concentration of particles
produced when the substance is dissolved, and the concentration of a substance as calculated
from its mass. For most non-electrolytes dissolved in water, the van\' t Hoff factor is essentially
1. For most ionic compounds dissolved in water, the van \'t Hoff factor is equal to the number of
discrete ions in a formula unit of the substance. This is true for ideal solutions only, as
occasionally ion pairing occurs in solution. At a given instant a small percentage of the ions are
paired and count as a single particle. Ion pairing occurs to some extent in all electrolyte
solutions. This causes deviation from th.

1. The van \'t Hoff factor i (named after J. H. van \'t Hoff) is a measure of the effect of a solute
upon colligative properties, such as vapor pressure, osmotic pressure and freezing point
depression. The van \'t Hoff factor is the ratio between the actual concentration of particles
produced when the substance is dissolved, and the concentration of a substance as calculated
from its mass. For most non-electrolytes dissolved in water, the van\' t Hoff factor is essentially
1. For most ionic compounds dissolved in water, the van \'t Hoff factor is equal to the number of
discrete ions in a formula unit of the substance. This is true for ideal solutions only, as
occasionally ion pairing occurs in solution. At a given instant a small percentage of the ions are
paired and count as a single particle. Ion pairing occurs to some extent in all electrolyte
solutions. This causes deviation from the van \'t Hoff factor. The deviation for the van \'t Hoff
factor tends to be greatest where the ions have multiple charges.

Relationship with the dissociation degree

The dissociation degree is the fraction of original solute molecules that have dissociated. It is
usually indicated by the Greek symbol . There is a simple relationship between this parameter
and the van \'t Hoff factor. If the solute substance dissociates into n ions, then

i = 1 + (n 1)
For instance, for the following dissociation

KCl K+ + Cl-
As n = 2, we would have that i = 1 +

Physical significance of i

When solute particles associate in solution, i is less than 1. (e.g. ethanoic acid in benzene,
benzoic acid in benzene)
When solute particles dissociate in solution, i is greater than 1. (e.g. sodium chloride in water,
potassium chloride in water, magnesium chloride in water)
When solute particles neither dissociate nor associate in solution, i equals 1. (e.g. Glucose in
water)
The value of i is ; i = the actual number of particles in solution after dissociation ÷ the number
of formula units initially dissolved in solution. Means the number of particles per formula unit of
the solute when a solution is dilute.

2. Solution

The van \'t Hoff factor i (named after J. H. van \'t Hoff) is a measure of the effect of a solute
upon colligative properties, such as vapor pressure, osmotic pressure and freezing point
depression. The van \'t Hoff factor is the ratio between the actual concentration of particles
produced when the substance is dissolved, and the concentration of a substance as calculated
from its mass. For most non-electrolytes dissolved in water, the van\' t Hoff factor is essentially
1. For most ionic compounds dissolved in water, the van \'t Hoff factor is equal to the number of
discrete ions in a formula unit of the substance. This is true for ideal solutions only, as
occasionally ion pairing occurs in solution. At a given instant a small percentage of the ions are
paired and count as a single particle. Ion pairing occurs to some extent in all electrolyte
solutions. This causes deviation from the van \'t Hoff factor. The deviation for the van \'t Hoff
factor tends to be greatest where the ions have multiple charges.

Relationship with the dissociation degree

The dissociation degree is the fraction of original solute molecules that have dissociated. It is
usually indicated by the Greek symbol . There is a simple relationship between this parameter
and the van \'t Hoff factor. If the solute substance dissociates into n ions, then

i = 1 + (n 1)
For instance, for the following dissociation

KCl K+ + Cl-
As n = 2, we would have that i = 1 +

Physical significance of i

When solute particles associate in solution, i is less than 1. (e.g. ethanoic acid in benzene,
benzoic acid in benzene)
When solute particles dissociate in solution, i is greater than 1. (e.g. sodium chloride in water,
potassium chloride in water, magnesium chloride in water)
When solute particles neither dissociate nor associate in solution, i equals 1. (e.g. Glucose in
water)
The value of i is ; i = the actual number of particles in solution after dissociation ÷ the number

3. of formula units initially dissolved in solution. Means the number of particles per formula unit of
the solute when a solution is dilute.