Chemistry of Metals and Alloys

1. Argentite $Ag _2S$
2.  Galena $PbS$
3.  Chalcocite $Cu _2S$
4.  Copper pyrite (chalco pyrite)$ [CuFeS _2]$
5.  Cassiiterite $SnO _2$
6.  Dolomite  [$ Ca Mg (CO _3) _2$]
7.  Bauxite $Al(OH) _3$

∴ Sulphide containing ores are$ Ag, Cu, Pb.$

Option A is correct.

Ag and Pt are found in native (free) state.
Native silver usually occurs associated with coppr and gold, e.g., in alluvial sands.

Sodium (alkali metal) is highly reactive and so, it occurs as a compound i.e. in combined form like NaCl.

Aluminum is the most abundant metal in the earth's crust but it is never found free in nature. Silicon is not a metal.

Silicon is the most abundant element in the earth crust. It is found in rocks .

Aluminium is the most abundant element in the earth's crust. It is most abundant in terms of quantity.

A noble metal is any metal that is found in its metallic form, either pure or alloyed, in nature. Over geological time scales, very few metals can resist natural weathering processes like oxidation, which is why generally only the less reactive metals such as gold and platinum are found as noble metals.

Gold and silver are extracted from their native ores by leaching. Leaching involves the treatment of the ore with suitable reagent as to make it soluble while impurities remain insoluble.

Iron, Nickel, Chromium

Matte contains mainly ${Cu} _{2}S$ and $FeS$. It also contains coke and sand. It is the molten metal obtained from the blast furnace.

Chromium (Cr) metal is present in Ruby as an impurity. Ruby has pink to blood-red colour. It is a  gemstone. It is a variety of the mineral corundum (aluminium oxide).

Iron was the primary material used for machinery, bridges, and infrastructure during the early Industrial Revolution. Steel became dominant later during the Second Industrial Revolution.

Copper has very low electrical resistivity, making it an excellent conductor for wiring.

Nichrome is an alloy with high electrical resistance and a high melting point, making it ideal for heating elements in appliances like electric irons.

People first began making things from metal over 9000 years ago, when they discovered how to get copper from its ore. They then learned how to make a harder alloy, bronze, by adding tin to the copper. About 3000 years ago, they discovered iron.