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 ?
-
A.
some CuO was reacted with excess dilute H2SO4 -
B.
the solution was concentrated -
C.
when the concentrate was cooled, crystals formed were removed by filtration -
D.
the crystals were washed with very little cold water -
E.
the crystals were then allowed to dry