Below is a question from the 2017 USNCO:
The concentration of which approximately 0.01M solution could be most accurately determined by a visible spectrophotometer (or colorimeter)?
The answer sheet states B is the correct answer.
I researched the colours of the ions in solution, and found:
- Mn is pink
- Co is pink
- Zn is clear
- Pb is clear
I was unsure how to progress from there.
How should I approach this question in an exam if there was no reference book?