When a sulphide ore of a noble metal is treated with excess of cyanide solution then a soluble complex is formed which when treated with Zn, a soluble complex (X) is formed and noble metal is obtained

Question

When a sulphide ore of a noble metal is treated with excess of cyanide solution then a soluble complex is formed which when treated with Zn, a soluble complex (X) is formed and noble metal is obtained as residue. Which of the following statement is correct regarding (X)

TestHub · Accepted Answer

The soluble complex (X) formed in this MacArthur-Forrest cyanide process is $N a_{2} [Z n (CN)_{4}]$ .

Statement A is correct because zinc exists within the anionic coordination sphere as $[Z n (CN)_{4}]^{2 -}$ .

Statement B is incorrect because $Z n^{2 +}$ has a completely filled $3 d^{10}$ configuration, forcing sp³ hybridization instead of dsp².

Statement C is correct since the Effective Atomic Number (EAN) equals $A t o mi c N u mb er (30) - O x i d a t i o n St a t e (2) + 2 \times C oor d ina t i o n N u mb er (4) = 36$ .

Statement D is correct because $C N^{-}$ acts as a $π$ -acceptor ligand that undergoes back-bonding (synergic bonding) with the metal.

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