NaCN is sometimes added in the froth floatation process as depressant when ZnS and PbS minerals are — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

Step 1: Highly reactive metals like alkali metals, alkaline earth metals, and rare earth metals have high electropositive character and easily form stable oxides, halides, or carbonates, meaning they are never found free in nature. Step 2: Metals with very low chemical reactivity and very positive reduction potentials (such as Gold, Platinum, and Silver) resist oxidation and chemical attack. Step 3: These unreactive metals are classified as noble metals and are expected to occur in their elemental (native) state in nature, matching option (c).