What is the weight/volume for a 0.2% solution?

Answer 1

It depends upon how much you want to make up; e.g., a cup, a liter, a tub?
In general, a 0.2%(w/v) solution can be made by dissolving 0.2 g (200 mg) of the solute in 100 mL of solution. For other volumes, just change the numbers.