Question

How do you separate a solution of copper nitrate?

Answer 1

You want to separate copper nitrate from what?

Explanation:

You could remove copper ion from solution by adding an anion (i.e. hydroxide, or sulfide) that forms an insoluble salt with the copper ion. But first you will have to specify what copper ion, `Cu^+` or `Cu^(2+)`, and give us a few more details of the problem.