When the salt of a particular metal is heated with solid Na2CO3 and Co(NO3)2 on a charcoal block, a blue-coloured ash (bead) is obtained. Which metal gives this result?

Question

Accepted Answer

Al. The cobalt nitrate test on charcoal is used to identify certain metal oxides. CoO (from Co(NO3)2 decomposition) reacts with Al2O3 to form cobalt aluminate, Co(AlO2)2, which is an intense blue compound. Mg gives white bead (Co·MgO), Zn gives green bead (Co·ZnO = Rinmann's green), and Cu gives black bead. Hence the blue ash indicates Al.

When the salt of a particular metal is heated with solid Na2CO3 and Co(NO3)2 on a charcoal block, a blue-coloured ash (bead) is obtained. Which metal gives this result?

Solution

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