Principle

The structures of molecules are not changed by their chemical
environment in the gas phase. In contrast to this, on transition to
the condensed phase, in dilute solution, the solvent changes the
binding state of the dissolved substance. One of the way this
influence makes itself shown is in the elctron spectrum
(solvatochromatic shift).

Tasks


Plot and discuss UV-VIS absorption spectra of methyl orange in
various solvents.

From the decadic molar extinction coefficients of the bands in
the visible range, determine the type of electron transition that
causes these bands.

Plot the wavelengths of the absorption maxima in the visible
range against the dielectric constants of the various
solvents.


What you can learn about


Absorption of light

Electron excitation

Influence of solvents

Solvatochromic, hypsochromic and bathochromic shifts

Lambert-Beer Law

Decadic molar extinction coefficient