When borax is heated with CoO on a platinum loop, blue coloured bead formed is largely due to : 2 3 — p Block Elements Chemistry Question

💡 Solution & Explanation

Borax , on heating gets fused and loses water of crystallisation. It swells up into a fluffy white porous mass which then melts into a colourless liquid and forms a clear transparent glass bead consisting of boric anhydride and sodium metaborate. Boric anhydride is non-volatile. When it is reacted with a coloured metallic salt, a characteristic coloured bead of metal metaborate is formed. Thus, when reacted to cobalt oxide, forms blue coloured bead.