Metallurgy · JEE Main previous year questions

In the extraction of copper from its sulphide ore, metal is finally obtained by the oxidation of cuprous sulphide with :

1. A.$\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$
2. B.$\mathrm{C}{\mathrm{u}}_2\mathrm{O}$
3. C.$\mathrm{S}{\mathrm{O}}_2$
4. D.$\mathrm{CO}$

The following reaction occurs in the Blast Furnace where iron ore is reduced to iron metal : $\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3(\mathrm{s})+3\mathrm{CO}(\mathrm{g})\rightleftharpoons 2\mathrm{Fe}(\mathrm{l})+3\mathrm{C}{\mathrm{O}}_2(\mathrm{g})$ Using the Le Chatelier’s principle, predict which one of the following will not disturb the equilibrium ?

1. A.Removal of $\mathrm{CO}$
2. B.Removal of $\mathrm{C}{\mathrm{O}}_2$
3. C.Addition of $\mathrm{C}{\mathrm{O}}_2$
4. D.Addition of $\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$

Which one of the following ores is best concentrated by froth floatation method?

1. A.Siderite
2. B.Galena
3. C.Malachite
4. D.Magnetite

Which of the following compounds is not colored yellow?

1. A.${\mathrm{K}}_3[\mathrm{Co}(\mathrm{N}{\mathrm{O}}_2{)}_6]$
2. B.$(\mathrm{N}{\mathrm{H}}_4{)}_3[\mathrm{As}(\mathrm{M}{\mathrm{o}}_3{\mathrm{O}}_{10}{)}_4]$
3. C.$\mathrm{BaCr}{\mathrm{O}}_4$
4. D.$\mathrm{Z}{\mathrm{n}}_2[\mathrm{Fe}(\mathrm{CN}{)}_6]$

In the context of the Hall-Heroult process for the extraction of Al, which of the following statements is false?

1. A.$\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$ is mixed with $\mathrm{Ca}{\mathrm{F}}_2$ which lowers the melting point of the mixture and brings conductivity
2. B.$\mathrm{A}{\mathrm{l}}^{3+}$ is reduced at the cathode to form Al
3. C.$\mathrm{N}{\mathrm{a}}_3\mathrm{Al}{\mathrm{F}}_6$ serves as the electrolyte
4. D.$\mathrm{CO}$ and $\mathrm{C}{\mathrm{O}}_2$ are produced in this process

The substance used as froth stabilisers in froth-floatation process is

1. A.Potassium ethyl xanthate
2. B.Aniline
3. C.Sodium cyanide
4. D.Copper sulphate

$5\mathrm{g}$ of benzene on nitration gave $6.6\mathrm{g}$ of nitrobenzene. The theoretical yield of the nitrobenzene will be

1. A.$4.5\mathrm{g}$
2. B.$5.6\mathrm{g}$
3. C.$8.09\mathrm{g}$
4. D.$6.6\mathrm{g}$

Which one of the following ores is best concentrated by froth – floatation method?

1. A.Magnetite
2. B.Malachite
3. C.Galena
4. D.Cassiterite

The metal extracted by leaching with a cyanide is

1. A.Mg
2. B.Ag
3. C.Cu
4. D.Na