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CoS (black) obtained in group IV of salt...

`CoS` (black) obtained in group `IV` of salt analysis is dissolved in aqua regia and is treated with an excess of `NaHCO_(3)` and then `Br_(2)` water.An apple green coloured stable complex is formed. It is:

A

sodium cobaltocarbonate

B

sodium cobaltibromide

C

sodium cobalticarbonate

D

sodium cobaltobromide

Text Solution

Verified by Experts

The correct Answer is:
C
`2CoS+6HCl+2HNOto3CoCl_(2)+2NO+3S+4H_(2)O`
`CoCl_(2) + 6NaHCO_(3) to Na_(4)[Co(CO_(3))_(3)]+2NaCl+3H_(2)O+3CO_(2)`
`2Na_(4) [Co(CO_(3))_(3)]+Br_(2) to 2Na_(3) underset(("Green"))([Co(CO_(3))_(3)])+2NaBr`
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