In the preparation of some pure crystals of Cu (NO3)2 starting with CuO, a student gave the following statements as steps he employed. Which of these shows a flaw in his report ?
-
some CuO was reacted with excess dilute H2SO4
- the solution was concentrated
- when the concentrate was cooled, crystals formed were removed by filtration
- the crystals were washed with very little cold water
- the crystals were then allowed to dry