Q.Give the uses of Borax.

Step 1. Borax forms a clear, transparent bead when strongly heated (losing its water of hydration and then converting to 2NaBO₂ + B₂O₃) -- when a coloured transition-metal salt is fused into this bead, the metal oxide formed colours the bead characteristically, letting the metal ion be identified (the classic borax-bead test).

Step 2. Borax is used in the manufacture of optical and borosilicate glass, exploiting boron oxide's contribution to glass's thermal and optical properties, as well as in enamels and pottery glazes.

Step 3. It is used as a flux in metallurgy, helping molten metal oxides and slag flow and separate more easily during smelting and welding operations.

Step 4. It also serves as a preservative, drawing on its mild antiseptic/antimicrobial character.

List each of the chapter's four stated uses of borax and, where relevant, connect it back to the chemistry (the transparent bead) that makes that use possible.

• Giving only one or two uses when the chapter lists four distinct ones -- a 'give the uses' question expects the full stated list, not just the best-known application.