JAMB - Chemistry (1983 - No. 31)
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