Aluminium and zinc metal evolve H2 gas from NaOH solution. — p Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Heating borax on a platinum wire loop forms a transparent, glassy bead of sodium metaborate (NaBO2) and boric anhydride (B2O3). Step 2: When this hot bead is touched to a transition metal salt and heated again, the metal oxide reacts with B2O3 to form colored transition metal metaborates. Step 3: Because the characteristic colored beads are formed by these specific transition metal metaborates, option (c) is the correct choice.