99. Calculate the concentration of copper (in mol / l)

The seller is blocked and sales of the product are suspended

99. Calculate the concentration of copper (in mol / l) in the solution if, when analyzing 10 ml of the test solution by the method of additives, a wave height of 20.5 mm was obtained, after adding 2 ml of a standard solution with a concentration of 0.05 mol / l, the wave height increased up to 24 mm.