Metallurgy · JEE Main previous year questions

Given below are two statements : Statement I : $({\text{CH}}_3{)}_3\stackrel{\oplus }{C}$ is more stable than $\stackrel{\oplus }{C}{\text{H}}_3$ as nine hyperconjugation interactions are possible in $({\text{CH}}_3{)}_3\stackrel{\oplus }{C}$. Statement II : $\stackrel{\oplus }{C}{\text{H}}_3$ is less stable than $({\text{CH}}_3{)}_3\stackrel{\oplus }{C}$ as only three hyperconjugation interactions are possible in $\stackrel{\oplus }{C}{\text{H}}_3$. In the light of the above statements, choose the correct answer from the options given below

1. A.Statement I is false but Statement II is true
2. B.Statement I is true but Statement II is false
3. C.Both Statement I and Statement II are true
4. D.Both Statement I and Statement II are false

1. A.(A) & (B) only
2. B.(B) & (D) only
3. C.(A) & (C) only
4. D.(B) & (C) only

If $\mathrm{C}(\mathrm{diamond})\to \mathrm{C}(\mathrm{graphite})+X\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$ $\mathrm{C}(\mathrm{diamond})+{\mathrm{O}}_2(\mathrm{g})\to \mathrm{C}{\mathrm{O}}_2(\mathrm{g})+Y\mathrm{kJmo}{\mathrm{l}}^{-1}$ $\mathrm{C}(\mathrm{graphite})+{\mathrm{O}}_2(\mathrm{g})\to \mathrm{C}{\mathrm{O}}_2(\mathrm{g})+Z\mathrm{kJmo}{\mathrm{l}}^{-1}$ at constant temperature. Then

1. A.$-X=Y+Z$
2. B.$X=Y-Z$
3. C.$X=-Y+Z$
4. D.$X=Y+Z$

Given below are two statements: Statement I: The conversion proceeds well in the less polar medium. $$\mathrm{C}{\mathrm{H}}_3-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{Cl}\stackrel{\mathrm{H}{\mathrm{O}}^{-}}{\to }\mathrm{C}{\mathrm{H}}_3-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{OH}+\mathrm{C}{\mathrm{l}}^{(-)}$$ Statement II: The conversion proceeds well in the more polar medium. $$\mathrm{C}{\mathrm{H}}_3-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{Cl}\stackrel{{\mathrm{R}}_3\ddot{\mathrm{N}}}{\to }\mathrm{C}{\mathrm{H}}_3-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\underset{\underset{\mathrm{R}}{|}}{\stackrel{\stackrel{\mathrm{R}}{|}}{\underset{(+)}{\mathrm{N}}}}-\mathrm{R}\mathrm{C}{\mathrm{l}}^{(-)}$$ In the light of the above statements, choose the correct answer from the options given below

1. A.Statement I is false but Statement II is true
2. B.Statement I is true but Statement II is false
3. C.Both Statement I and Statement II are false
4. D.Both Statement I and Statement II are true

The fusion of chromite ore with sodium carbonate in the presence of air leads to the formation of products A and B along with the evolution of $\mathrm{C}{\mathrm{O}}_2$. The sum of spin-only magnetic moment values of A and B is ____ B.M. (Nearest integer) [Given atomic number : $\mathrm{C}:6,\mathrm{Na}:11,\mathrm{O}:8,\mathrm{Fe}:26,\mathrm{Cr}:24$]

The fragrance of flowers is due to the presence of some steam volatile organic compounds called essential oils. These are generally insoluble in water at room temperature but are miscible with water vapour in vapour phase. A suitable method for the extraction of these oils from the flowers is -

1. A.distillation
2. B.steam distillation
3. C.distillation under reduced pressure
4. D.crystallisation

Given below are two statements related to Ellingham diagram: Statement I : Ellingham diagrams can be constructed for formation of oxides, sulfides and halides of metals. Statement II : It consists of plots of ${\Delta }_{\mathrm{f}}{\mathrm{H}}^0$ vs $\mathrm{T}$ for formation of oxides of elements. In the light of the above statements, choose the most appropriate answer from the options given below:

1. A.Both Statement I and Statement II are correct
2. B.Both Statement I and Statement II are incorrect
3. C.Statement I is correct but Statement II is incorrect
4. D.Statement I is incorrect but Statement II is correct

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : In the Ellingham diagram, a sharp change in slope of the line is observed for $\mathrm{Mg}\to \mathrm{MgO}$ at $\sim 1120^{\circ }\mathrm{C}$ Reason R: There is a large change of entropy associated with the change of state In the light of the above statements, choose the correct answer from the options given below

1. A.Both A and R are true and R is the correct explanation of A
2. B.A is false but R is true
3. C.Both A and R are true but R is NOT the correct explanation of A
4. D.A is true but R is false

Given below are two statements : Statement I : In the metallurgy process, sulphide ore is converted to oxide before reduction. Statement II : Oxide ores in general are easier to reduce. In the light of the above statements, choose the most appropriate answer from the options given below:

1. A.Both Statement I and Statement II are correct
2. B.Both Statement I and Statement II are incorrect
3. C.Statement I is correct but Statement II is incorrect
4. D.Statement I is incorrect but Statement II is correct

Which of the following is used as a stabilizer during the concentration of sulphide ores?

1. A.Cresols
2. B.Xanthates
3. C.Fatty acids
4. D.Pine oils

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : The energy required to form ${\text{Mg}}^{2+}$ from $\text{Mg}$ is much higher than that required to produce ${\text{Mg}}^{+}$ Reason R : ${\text{Mg}}^{2+}$ is a small ion and carries more charge than ${\text{Mg}}^{+}$ In the light of the above statements, choose the correct answer from the options given below.

1. A.A is false but R is true
2. B.Both A and R are correct but R is NOT the correct explanation of A
3. C.Both A and R are correct and R is the correct explanation of A
4. D.A is true but R is false

Which of the following metals can be extracted through alkali leaching technique?

1. A.$\mathrm{Sn}$
2. B.$\mathrm{Cu}$
3. C.$\mathrm{Au}$
4. D.$\mathrm{Pb}$

Given below are two statements: Statement I : Methyl orange is a weak acid. Statement II : The benzenoid form of methyl orange is more intense/deeply coloured than the quinonoid form. In the light of the above statement, choose the most appropriate answer from the options given below:

1. A.Both Statement I and Statement II are incorrect
2. B.Statement I is incorrect but Statement II is correct
3. C.Both statement I and Statement II are correct
4. D.Statement I is correct but Statement II is incorrect

The possibility of photochemical smog formation is more at :

1. A.Industrial areas
2. B.Himalayan villages in winter
3. C.The places with healthy vegetation
4. D.Marshy lands

1. A.B and D only
2. B.B, C and D only
3. C.A, B and D only
4. D.A, B and C only

The number of colloidal systems from the following, which will have 'liquid' as the dispersion medium, is ___________. Gem stones, paints, smoke, cheese, milk, hair cream, insecticide sprays, froth, soap lather

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: In an Ellingham diagram, the oxidation of carbon to carbon monoxide shows a negative slope with respect to temperature. Reason R: CO tends to get decomposed at higher temperature. In the light of the above statements, choose the correct answer from the options given below

1. A.A is correct but R is not correct
2. B.Both A and R are correct but R is NOT the correct explanation of A
3. C.A is not correct but R is correct
4. D.Both A and R are correct and R is the correct explanation of A

The methods NOT involved in concentration of ore are A. Liquation B. Leaching C. Electrolysis D. Hydraulic washing E. Froth floatation Choose the correct answer from the options given below :

1. A.A and C only
2. B.C, D and E only
3. C.B, D and C only
4. D.B, D and E only

In the extraction of copper, its sulphide ore is heated in a reverberatory furnace after mixing with silica to:

1. A.remove $\mathrm{FeO}$ as ${\mathrm{FeSiO}}_3$
2. B.remove calcium as ${\mathrm{CaSiO}}_3$
3. C.decrease the temperature needed for roasting of ${\mathrm{Cu}}_2\mathrm{S}$
4. D.separate $\mathrm{CuO}$ as ${\mathrm{CuSiO}}_3$

The reaction representing the Mond process for metal refining is ____.

1. A.$\mathrm{ZnO}+\mathrm{C}\stackrel{\mathrm{\Delta }}{\to }\mathrm{Zn}+\mathrm{CO}$
2. B.$2K[\mathrm{Au}(\mathrm{CN}{)}_2]+\mathrm{Zn}\stackrel{\mathrm{\Delta }}{\to }{\mathrm{K}}_2[\mathrm{Zn}(\mathrm{CN}{)}_4]+2Au$
3. C.$\mathrm{Zr}+2{\mathrm{I}}_2\stackrel{\mathrm{\Delta }}{\to }\mathrm{Zr}{\mathrm{I}}_4$
4. D.$\mathrm{Ni}+4CO\stackrel{\mathrm{\Delta }}{\to }\mathrm{Ni}(\mathrm{CO}{)}_4$

The major component of which of the following ore is sulphide based mineral?

1. A.Sphalerite
2. B.Siderite
3. C.Malachite
4. D.Calamine

Given below are two statements : Statement I : In froth floatation method a rotating paddle agitates the mixture to drive air out of it. Statement II : Iron pyrites are generally avoided for extraction of iron due to environmental reasons. In the light of the above statements, choose the correct answer from the options given below :

1. A.Statement I is true but Statement II is false
2. B.Statement I is false but Statement II is true
3. C.Both Statement I and Statement II are true
4. D.Both Statement I and Statement II are false

The metal which is extracted by oxidation and subsequent reduction from its ore is :

1. A.Al
2. B.Cu
3. C.Ag
4. D.Fe

In metallurgy the term "gangue" is used for :

1. A.Contamination of undesired earthy materials.
2. B.Contamination of metals, other than desired metal.
3. C.Minerals which are naturally occurring in pure form
4. D.Magnetic impurities in an ore.