Aqueous sodium hydroxide was added drop by drop, and then in excess, to separate solutions of W, X, Y and Z. The outcomes are shown. Which row identifies the metal ions in the solutions?
- AW: aluminium; X: calcium; Y: copper(II); Z: iron(II)
- BW: aluminium; X: calcium; Y: iron(II); Z: copper(II)
- CW: aluminium; X: iron(II); Y: calcium; Z: copper(II)
- DW: calcium; X: aluminium; Y: copper(II); Z: iron(II)