3. What experimental problems would you encounter if you attempted to determine the concentration of the metal ions in solutions of each of the following reagents?
a. Cr3+ which has a maximum absorbance at 407 nm with ε=15M−cm−and another at 574 nm with ε =13M−cm−
b. Mn2+ which has a maximum absorbance at 530 nm with ε=0.050M−cm−