It should be possible for many, but not for all, considering that some oxydation states may be colorless whereas others are poorly soluble. Therefore, the spectrometer may not detect them while present. Others will appear as precipitates, depending on the pH, making the measurement cell very turbid and therefore inadapted to the technique. Finally, some low oxidation states are extremely sensitive to dissolved oxygen, and should be kept in a protective atmosphere for being observed. In conclusion, this method should be limited to the most simple cases, e.g. Fe(II) - Fe(III) in acidic medium.

Alain

Yes, You can do. because when the oxidation change of the metals particularly transition group elements change their color and conveniently followed by UV-Visble spectometry

It should be possible for many, but not for all, considering that some oxydation states may be colorless whereas others are poorly soluble. Therefore, the spectrometer may not detect them while present. Others will appear as precipitates, depending on the pH, making the measurement cell very turbid and therefore inadapted to the technique. Finally, some low oxidation states are extremely sensitive to dissolved oxygen, and should be kept in a protective atmosphere for being observed. In conclusion, this method should be limited to the most simple cases, e.g. Fe(II) - Fe(III) in acidic medium.

Alain

Alain has given it all. UV-Visible spectrometry  is based on colour change, so for those metals that their change in oxidation states are marked by prominent colour change can easily be followed using such method.

yes, I agree with above answers to use UV-Visible spectroscopy for kinetic study. 

Another consideration is how clean the conversion is.  If the spectral changes go from the original spectrum to the final spectrum with clean isosbestic points, and you know the extinction coefficients for each species it is possible.  This also assumes that your oxidant or reductant does not have any absorbance in the region where the spectral changes are occuring.  

A very general question has a very general answer: yes but not always. This depends on your reaction 

An additional point to consider is the change in potential depending on the ligands. For instance, Alain mentioned Fe(II) and Fe(III) in acidic medium, but the potential varies even at acid pH based on if it is iron-hexaaqua or pentaaqua iron with a hydroxide. Additionally, you must beware pH dependent dimerization of certain aqueous iron species.

In short: you can do it, but there are many considerations to be made.

It is perfect for coloured ions but it is also possible for those that are not too coloured. Such later ions also have characteristic absorptions at particular wavelengths in the UV region and so can be monitored with appropriate knowledge of literature and conditions.

There are numerous papers on kinetics where a metal is used as an oxidant or as a reductant. In a particular reaction system, the parameters are to be carefully fixed and then the kinetics can be followed using a spectrophotometer. It does not matter whether the reaction system is colored or colorless.