3.6. Copper solution (stock): weigh, to the nearest 0,001 gram, 1 gram of pure copper, dissolve in 25 ml 6 mol/l hydrochloric acid solution (3.2), add 5 ml of hydrogen peroxide (3.5) in portions and dilute to 1 litre with water.
3.6. Koperoplossing (stockoplossing): weeg 1 g zuiver koper tot op 0,001 g nauwkeurig af, los dit op in 25 ml van 6 mol/l-zoutzuuroplossing (3.2), voeg 5 ml waterstofperoxide (3.5) in delen toe en vul met water aan tot 1 liter.