Question

Which of the following metals is present in native state?
A.platinum
B.iron
C.potassium
D.copper

Answer 1

Any metal that is found pure in its metallic form in nature is called native metal. Only some metals can resist natural weathering processes like oxidation over geological time scales, so mostly the less reactive metals are found as native metals.

Complete step by step answer:
There are very few metals that exist in the free or native state. Some metals like platinum, mercury and gold only, are at times found in the free state, that is in the pure form. Platinum is one of the least reactive metals. It has extraordinary resistance to corrosion, even at very high temperatures, and therefore it is considered a noble metal. Thus, platinum is often found chemically not combined as native platinum. This is because it occurs naturally in the alluvial sands of various rivers. Natural alloys of the platinum group metals include, Ruthe iridosmine (Ir, Os, Ru), native osmium (Os, Ir, Ru), ruthenium (Ru, Ir), platinum Pt, palladium (Pd, Pt), and rhodium (Rh, Pt). In addition, copper, iron, gold, mercury, lead and tin may occur in alloys of this group. As with gold, salts and other compounds of the platinum group metals are rare; native platinum and related metals and alloys are the main minerals bearing these metals. These metals occur associated with ultramafic intrusions and placer deposits derived from those intrusions.

Therefore, the correct answer is option (A).

Note: Pure platinum is a ductile, malleable, and lustrous, silver-white metal. Platinum is more ductile than gold, silver or copper, and being the most ductile of pure metals, but it is also less malleable than gold. This metal has excellent resistance to corrosion and is stable at high temperatures. It has stable electrical properties and Platinum does oxidize.