The substances that are capable of withstanding very high temperatures without melting or becoming soft are called refractory materials like- SiC (carborundum), Al₂O₃, SiO_2, etc. Blast furnace is used for the smelting of iron, copper and lead ores. Calamine (ZnCO₃) is the ore of zinc while casseterite (SnO₂) is the ore of Sn.

The percentage of copper in cuprite (Cu₂O) is 88.8%. Hence, cuprite has the maximum purity among all the given minerals.

Sylvine (KCl) and rock salt (NaCl) are the ores of potassium and sodium respectively. Wood metal consists of Bi = 50%, Pb = 25%, Sn = 12.5% & Cd = 12.5% and is used in the making of automatic sprinklers as it melts in hot water (m.p.= 68 ^oC). Duralumin is used in the manufacturing of aeroplane parts and consists of Al = 95.5%, Cu = 4%, Mg = 0.5% and Mn = 0.5%.

Copper ores are - covellite (CuS), chalcopyrite (CuFeS₂), bornite (2Cu₂S.CuS.FeS), etc. Anglesite (PbSO₄) is the ore of lead.

A. Copper has very good anti-corrosive property and is used for making wires used in electrical industry and for water and steam pipes. B. German silver contains Cu 25-30%, Zn 25-30% and Ni 40–50%. C. Zinc dust is used as a reducing agent in the manufacture of dye-stuffs, paints, etc. and in a several organic and inorganic synthesis reactions.

Cerussite (PbCO₃) is the carbonate ore of Pb.

Type metal is composed of 82% Pb, 15% Sb and 3% Sn. Gun metal consists of 88% Cu, 10% Sn, 2% Zn and 0.5% Pb. Pewter alloy is composed of 76% Sn and 24% Pb. Rose metal consists of 50% Bi, 25% Pb and 25% Sn. Hence, the correct answer using the codes is P - 3, Q - 1, R - 4, S - 2.

Fusible alloys are generally composed of Bi, Pb and Sn. They melt at comparatively low temperatures, below the melting point of tin. Examples are- Newton’s alloy (contains 50% Bi, 31.25% Pb and 18.75% Sn), Jean Darcet’s alloy (contains 50% Bi, 25% Pb and 25% Sn), etc. Dow’s alloy or Dow metal is an example of light metal alloys. Dow metal contains 93.8% Mg, 6% Al and 0.2% Mn.

Angelesite (PbSO₄) is the oxide ore of lead.

Pewter alloy is composed of 76% Sn and 24% Pb. Duralumin is composed of 94% Al, 4% Cu, and 2% Mg, Mn & Si. Dow metal contains 93.8% Mg, 6% Al, 0.2% Mn. Rose metal consists of 50% Bi, 25% Pb and 25% Sn. Hence, the answer using the codes is A - 5, B - 1, C - 3, D - 2.

Field's metal, or Field's alloy is a fusible alloy that becomes liquid at approximately 62^oC. It has 51% In, 32.5% Bi and 16.5% Sn.

1. 18-carot gold contains Au 75%, Ag 10–20% and Cu 5–15%. Gold 14-carot consists of Au 58%, Cu 12–28% and Ag 4–30%.
   1. Sterling-S (sterling silver) alloy is composed of Ag 92.5% and Cu 7.5%.
   2. The composition of Naval brass is Cu 60%, Zn 39.25% and Sn 0.75%.4. Dow’s metal is composed of 93.8% Mg, 6% Al and 0.2% Mn. Hence, both 1 and 2 are false.

The ores of iron are- Marcasite or iron pyrite (FeS₂): sulphide ore, Haematite (Fe₂O₃): oxide ore, Magnetite (Fe₃O₄): oxide ore, Orpiment (As₂S₃) is the sulphide ore of arsenic.

Cupronickel is composed of Cu 88.35%, Ni 10%, Fe 1.25% and Mn 0.4. Hence, cupronickel has iron as constituent.

Iron pyrite (FeS₂) has a yellow metallic appearance and so it is called fool’s gold because it had been mistaken for gold in ancient times.

Spinel (MgAl₂O₄) is the mineral of Mg and aluminium. Felspar (KAlSi₃O₈) is the mineral of potassium and aluminium. Cerussite (PbCO₃) is the carbonate ore of lead. Malachite (Cu(OH)₂.CuCO₃) is the carbonate ore of copper. Hence, the correct sequence of the codes is A - 1, B - 3, C - 2, D - 4.

A. Mild steel contains 0.15% to 0.30% of carbon. Medium steel has 0.30% to 0.60% of carbon. B. Promoted iron is used as the catalyst in the Haber-Bosch process for the making of NH₃. C. Mild steel is malleable and can be bent or machined. This is hardened (tempered) by heating to red heat and quenched by plunging into water or oil.

Megallium is composed of 60% cobalt, 20% chromium, 5% molybdenum and traces of other substances. Elinvar consists of 59% iron, 36% nickel, and 5% chromium.

Wulfenite is a lead molybdate mineral with the formula PbMoO₄. It is most often found as thin tabular crystals with a bright orange-red to yellow-orange colour, sometimes brown, although the colour can be highly variable.

Azurite (2CuCO₃.Cu(OH)₂) is commonly known as mountain blue or American stone.

P. Cuprite (Cu₂O) has 88.8% copper while chalcocite (Cu₂S) has 79.8% copper. Q. Chalcopyrite is called blister copper. It has the chemical composition CuFeS₂. Chalcocite (Cu₂S), is an important copper ore. It is also known as redruthite or vitreous copper. R. Goethite is hydroxide ore of iron with the chemical formula of FeO(OH).

Field's metal has 51% In, 32.5% Bi and 16.5% Sn.

Linotype metal alloy contains 86% Pb, 11% Sb and 3% Sn and has been used for over five centuries in printing processes.

Carrolow 117 consists of 44.7% Bi, 22.6% Pb, 8.3% Sn, 19.1% In and 5.3% Cd.

Lead free galvanizing solder (galvanite) formulation designed specifically for high quality repairs to galvanized steel surfaces. It is composed of tin 50%, zinc 49% and copper 1%.

Ounce’s metal is composed of Cu 85%, Zn 5%, Pb 5% and Sn 5%.

Direct-heat resistance furnace is an electric furnace in which heat is generated directly in the material to be heated. Direct-heat resistance furnaces are used for melting and heating of metals. Typical applications are- manufacture of graphite, carbon and various carbides like- silicon-carbide, boron-carbide, etc. Bessemer convertor is a pear shaped furnace, made up of steel plates and lined with silicious material. It is used in the manufacture of steel and in the metallurgy of copper.

Cassiterite is a tin oxide mineral with the chemical formula of SnO₂. Galena is the sulphide ore of lead with chemical formula of PbS. Limonite is the hydroxide ore of iron with the chemical formula of FeO(OH). Dolomite (CaMg(CO₃)₂) is also known as dolostone. It is the carbonate mineral of Ca and Mg. Hence, the correct answer using the codes is A - 3, B - 1, C - 4, D - 2.

Prince’s metal is a type of alpha brass. Due to its yellow colour, it is used as an imitation of gold. Also called Prince Rupert's metal, the alloy was named after Prince Rupert of the Rhine. The composition of prince’s metal contains 75% copper and 25% zinc.

P. Linotype metal alloy contains 86% Pb, 11% Sb and 3% Sn and has been used for over five centuries in printing processes. This alloy has low melting point, good stability and undergoes minimum contraction on solidification. Q. Wood’s metal is composed of 50% Pb, 25% Sn, 12.5% Cd and 12.5% Bi. This alloy has melting point of 80 ^oC and is used in soldering. R. Monotype metal contains 78% Pb, 15% Sb and 7% Sn.

Zincite (ZnO) is the oxide ore of zinc.

Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in colour from dark grey, bright yellow, deep purple, to rusty red. The oxide ores of iron are - magnetite (Fe₃O₄), haematite (Fe₂O₃) and limonite (Fe₂O₃.3H₂O). Siderite (FeCO₃) is the carbonate ore of iron.

P. The Parkes process, patented in 1850, uses zinc to form a material which the silver enters. This floats on the lead and can be skimmed off.
Q. The Pattison process was patented by its inventor, Hugh Lee Pattinson, in 1833. It depended on well-known material properties; essentially that lead and silver melt at different temperatures. The equipment consisted of a row of about 8-9 iron pots, which could be heated from below. Argentiferous lead was charged to the central pot and melted. This was then allowed to cool, as the lead solidified, it was skimmed off and moved to the next pot in one direction, and the remaining metal was then transferred to the next pot in the opposite direction. The process was repeated in the pots successively, and resulted in lead accumulating in the pot at one end and silver in that at the other. R. Fire process - The initial product of copper smelting was impure black copper, which was then repeatedly melted to purify it, alternately oxidizing and reducing it. In one of the melting stages, lead was added. Gold and silver preferentially dissolved in this, thereby providing a means of recovering these precious metals. To produce purer copper suitable for making copper plates or hollow-ware, further melting processes were undertaken, using charcoal as fuel. The repeated application of such fire-refining processes was capable of producing copper that was 99.25% pure.

Galena (PbS) is the sulphide ore of Pb. Dolomite (CaCO₃.MgCO₃) is the carbonate ore of Mg. Mica (K₂O.3Al₂O₃.6SiO₂.2H₂O) is the silicate ore of Al. Pyrolucite (MnO₂) is an oxide ore of Mn. Hence, the correct answer using the codes is P - 1, Q - 4, R - 2, S - 3.

In case of extraction of iron, in roasting step all taken pure haematite converted to FeO that combines with oxygen and form Fe₂O₃. So, the final product of the roasting step is FeO₃ in the extraction of iron and thus there is no need of roasting.