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The extraction of Au by leaching with Na...

The extraction of Au by leaching with NaCN involves both oxidation and reduction. Justify giving equations.

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`4Au + 8NaCN + O_2 + 2H_2O to 4Na[Au(CN)_2] + 4 NaOH` [Oxidation ]
Here, Au is oxidised to `Au^(+)` ions.
`2Na [ Au (CN)_2] + Zn to Na_2[Zn(CN)_4] + 2Au` [ Reduction]
Here , `Au^(+)` ions are reduced to Au.
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ICSE-GENERAL PRINCIPLES AND PROCESSES OF ISOLATION OF ELEMENTS -EXERCISE (PART-II ( DESCRIPTIVE QUESTIONS )) (VERY SHORT ANSWER QUESTIONS)
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