Ebullioscopic constant

In

boiling point elevation.^[1]

It is the ratio of the latter to the former:

\Delta T_{\text{b}}=iK_{\text{b}}b

$i$ is the van 't Hoff factor, the number of particles the solute splits into or forms when dissolved.
$b$ is the molality of the solution.

A formula to compute the ebullioscopic constant is:^[2]

K_{\text{b}}={\frac {RMT_{\text{b}}^{2}}{1000\Delta H_{\text{vap}}}}

$R$ is the
ideal gas constant
.
$M$ is the molar mass of the solvent.
$T b$ is boiling point of the pure solvent in kelvin.
$Δ H vap$ is the molar enthalpy of vaporization of the solvent.

Through the procedure called

freezing point depression

).

This property of elevation of boiling point is a colligative property. It means that the property, in this case $Δ T$ , depends on the number of particles dissolved into the solvent and not the nature of those particles.

Values for some solvents

Solvent^[3]	$K b$ (in K⋅kg/mol)
Acetic acid	3.08
Benzene	2.53
Camphor	5.95
Carbon disulfide	2.34
Carbon tetrachloride	5.03
Chloroform	3.63
Cyclohexane	2.79
Diethyl ether	2.02
Ethanol	1.07
Water	0.512

References

^ "Ebullioscopic Constant". CHEMISTRY GLOSSARY.
^ Martin, Chaplin. "Colligative Properties". London South Bank University. London South Bank University.
^ P. W. Atkins, Physical Chemistry, 4th Ed., p. C17 (Table 7.2)

External links

Ebullioscopic constant calculator AD

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[1] "Ebullioscopic Constant". CHEMISTRY GLOSSARY.

[2] Martin, Chaplin. "Colligative Properties". London South Bank University. London South Bank University.

[3] P. W. Atkins, Physical Chemistry, 4th Ed., p. C17 (Table 7.2)

[1]

[2]

[3]

Values for some solvents

See also

References

External links