A sample with $x\,\text{mol}$ of $\text{Al}_2\text{Cl}_6$ is dissolved in water, producing solution W. To precipitate all of the aluminium as its hydroxide, $y\,\text{mol}$ of sodium hydroxide are needed. Next, more alkali is introduced to make the precipitate dissolve again, forming solution Z. Which of the following statements are correct?
- A1, 2 and 3 are correct
- B1 and 2 only are correct
- C2 and 3 only are correct
- D1 only is correct