a. If a solution appears to be violet, what range of wavelength would you use for analysis of the solution?

Question

b. How about if the solution was blue-green?

Answer 1

If the solution appears violet then violet is being transmitted and the other colours are being absorbed. So there are two choices,
you can either pick a visible wavelength that is being absorbed (see (Broken Link Removed) for wavelengths
or you could use the transmitted wavelength.
The same answer for blue-green.