11.28 When metal X is treated with sodium hydroxide, a white precipitate (A) is obtained, which is soluble in excess of to give soluble complex (B). Compound (A) is soluble in dilute to form compound (C). The compound (A) when heated strongly gives (D), which is used to extract metal. Identify (X), (A), (B), (C) and (D). Write suitable equations to support their identities.
In given information, when X is treated with the sodium hydroxide it gives A(white ppt) and it is soluble in excess of . Thus X must be aluminium. So, the white ppt of A is aluminium hydroxide.
The complex B is soluble in excess of sodium hydroxide So it means it is a sodium tetrahydroxy aluminate(II) complex.
Now, when we add dilute HCl to aluminium hydroxide it gives the compound C (Aluminum chloride).
And when compound (A) is heated strongly, it gives D and this compound used to extract metal X