Statement-1 : Cu 2 + and Cd 2 + ions react with KCN solution (in excess) forming the colourless soluble complexes. Statement-2 : Of these colourless soluble complexes only cadmium complex gives yellow

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Statement-1 : Cu 2 + and Cd 2 + ions react with KCN solution (in excess) forming the colourless soluble complexes. Statement-2 : Of these colourless soluble complexes only cadmium complex gives yellow precipitate with H 2 ​ S gas in slightly acidic medium.

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Statement-1 : Cu 2 + + 4 CN − → [ Cu ( CN ) 4 ​ ] 3 − (colourless) Cd 2 + + 4 CN − → [ Cd ( CN ) 4 ​ ] 2 − (colourless) Statement-2 : Cd 2 + complex is less stable, therefore, it reacts with H 2 ​ S forming yellow precipitate of CdS. Where as [ Cu ( CN ) 4 ​ ] 3 − is more stable and thus is unaffected by H 2 ​ S gas.

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