Metallurgy

Siderite ore is primarily consist of iron (II) carbonate $\left[\mathrm{FeCO}_3\right]$.

$\mathrm{FeCO}_3$ consist $48.2 \%$ iron.

Aluminium is extracted from its ore bauxite. The concentration of bauxite is done by the leaching process using concentrated NaOH .

Statement I Analysis:

Ellingham diagrams plot the standard Gibbs free energy change ($\Delta G^{\ominus}$) for the formation of various metal oxides as a function of temperature. The principle driving the choice of reducing agent is based on the relative thermodynamic stability of the oxides. A metal can reduce the oxide of another metal if the $\Delta G^{\ominus}$ for the formation of its own oxide is more negative (i.e., its line is lower on the diagram) than the $\Delta G^{\ominus}$ for the formation of the oxide to be reduced, at a given temperature. This means that the overall reduction reaction will have a negative $\Delta G^{\ominus}$, making it thermodynamically feasible. Therefore, Ellingham diagrams are indeed used to predict the choice of reducing agent.

Statement I is correct.

Statement II Analysis:

The thermodynamic stability of a compound is inversely related to its standard Gibbs free energy of formation ($\Delta G^{\ominus}$). A more negative (lower) value of $\Delta G^{\ominus}$ for the formation of a compound indicates greater thermodynamic stability of that compound. Conversely, a higher (less negative or more positive) value of $\Delta G^{\ominus}$ indicates lower stability. Therefore, a metal oxide with a higher $\Delta G^{\ominus}$ is less stable than an oxide with a lower $\Delta G^{\ominus}$.

Statement II is incorrect.

Based on the analysis:

Statement I is correct.

Statement II is not correct.

This corresponds to Option B.

The final answer is $\boxed{B}$

Iron is made from its ore in a blast furnace. The iron ore has an impurity called $X$.

To remove $X$, another chemical, $Y$, is added to the mixture.

The chemical $Y$ is calcium carbonate $(\mathrm{CaCO}_3)$.

When $Y$ is heated ($\Delta$), it breaks down into calcium oxide $(\mathrm{CaO})$ and carbon dioxide $(\mathrm{CO}_2)$:

$ \underset{(Y)}{\mathrm{CaCO}_3} \xrightarrow{\Delta} \mathrm{CaO} + \mathrm{CO}_2 $

Next, calcium oxide $(\mathrm{CaO})$ reacts with the impurity, silicon dioxide $(\mathrm{SiO}_2)$, which is $X$, to form a liquid waste called slag:

$ \mathrm{CaO} + \underset{(\text{ Impurity } X)}{\mathrm{SiO}_2} \longrightarrow \underset{(\text{ Slag })}{\mathrm{CaSiO}_3} $

So, $X$ is silicon dioxide $(\mathrm{SiO}_2)$, and $Y$ is calcium carbonate $(\mathrm{CaCO}_3)$.

$ \text { Zinc is obtained from sphalerite ore by distillation method. } $

Reaction (a) i.e

$ 2 \mathrm{Cu}_2 \mathrm{~S}+3 \mathrm{O}_2 \longrightarrow 2 \mathrm{Cu}_2 \mathrm{O}+2 \mathrm{SO}_2 $

copper extraction via roasting.

Reaction (b) i.e

$2 \mathrm{FeS}+3 \mathrm{O}_2 \longrightarrow 2 \mathrm{FeO}+2 \mathrm{SO}_2$ is use to remove iron oxide from copper ore.

Reaction (c) i.e

$\mathrm{FeO}+\mathrm{SiO}_2 \longrightarrow \mathrm{FeSiO}_3$ is removal of slag in copper extraction.

$\mathrm{SiO}_2+\mathrm{CaO} \longrightarrow \mathrm{CaSiO}_3$ is not related to copper extraction.

The correct matching of alloys (List I) with their uses (List II) is:

A (Li-Pb) - III (To make tetraethyl lead): Lithium-lead alloys are primarily used in the production of tetraethyl lead, a gasoline additive (although its use is now largely phased out due to environmental concerns).

B (Be-Cu) - IV (To make high strength springs): Beryllium-copper alloys possess high strength, excellent electrical conductivity, and good fatigue resistance, making them ideal for applications requiring high-strength springs.

C (Mg-Al) - I (In aircraft construction): Magnesium-aluminum alloys are lightweight and relatively strong, properties highly desirable in aircraft construction for fuel efficiency and structural integrity.

D (Na-Pb) - II (To make bearings for motor engines): Sodium-lead alloys, while not as common as other alloy types listed, find applications in specialized bearings due to their unique material properties under specific operating conditions. Their use in bearings for motor engines is a possible application, though less prevalent than others.

Therefore, the correct answer is Option B: A-III; B-IV; C-I; D-II. Note that while the original provided answer key listed D-III, the more accurate match for D (Na-Pb) is II, considering the context and common applications of the alloys.

Copper matte is a mixture of sulphides of copper and iron. $ \left(\mathrm{Cu}_{2} \mathrm{~S}+\mathrm{FeS}\right) $

Matte is a kind of mixture in which element is extracted before the final reduction.

Calcination is the process in which the ore (hydrated, carbonate or bicarbonate) of the metal is heated to a high temperature in absence or limited supply of air.

$ \mathrm{Fe}_{2} \mathrm{O}_{3} \cdot x \mathrm{H}_{2} \mathrm{O}(s) \xrightarrow{\Delta} \mathrm{Fe}_{2} \mathrm{O}_{3}(s)+x \mathrm{H}_{2} \mathrm{O}(g) $

Kaolinite is a clay mineral with chemical formula $ \mathrm{Al}_{2} \mathrm{Si}_{2} \mathrm{O}_{5}(\mathrm{OH})_{4} $. It is a silicate mineral with Al metal.

Calamine is a lotion used in medical field for itching treatment.

It has chemical composition of $ \mathrm{ZnCO}_{3} $.

It is a carbonate mineral of zinc metal.

Hence, $ X $ is aluminium and $ Y $ is zinc.

The major component of cements are silicon dioxide and calcium oxide. $\mathrm{SiO}_2$ is present in 61-67\%. CaO is in $19-23 \%$ composition.

Distillation process works when low melting point metal contain high boiling point impurities.

Low boiling metals e.g. zinc and mercury containing high boiling point impurities is separated by distillation, and pure metal is collected as distillate.

Deacon's process It is a process to obtain chlorine gas.

$ 4 \mathrm{HCl}+\mathrm{O}_2 \xrightarrow[723 \mathrm{~K}]{\mathrm{CuCl}_2} 2 \mathrm{Cl}_2+2 \mathrm{H}_2 \mathrm{O} $

Mond's process is a technique created by Ludwig Mond in 1890, to extract and purify nickel (Ni).

van-Arkel process also known as iodide process is used for commerical production of pure zirconium $(\mathrm{Zr})$. Zone refining is method to get metal of very high purity i.e. pure sample of Ga, Si, B etc.

Thus, $X, Y$ and Z are $\mathrm{Ni}, \mathrm{Zr}$ and Ga respectively.

In leaching, a suitable reagent (not water) dissolves the ore and not the impurities. Thus, leaching is a chemical method of seperation/ concentration of the ore from impurities.

Hacking is used in extraction of Al from bauxite.

The given process for extraction of silver is leaching. It is a process of concentration which involves treatment of the ore with a suitable reagent, so as to make it soluble while impurities remains insoluble.

An Ellingham diagram is a graph showing the temperature dependence of the stability of compounds.It is the plot drawn between standard Gibb's free energy ( $\Delta G^{\circ}$ ) and temperature ( $T$ ).

Thus, $X$ and $Y$ are $\Delta G^{\circ}$ and $T$ respectively.

The correct match is A-III, B-IV, C-II, D-I.

Zone refining is used for the purification of metals like Si, Ge, Ga which are used in semiconductors.

Poling is used to purify metal like copper that are in impure form of a copper oxide. Liquation is the method in which low melting point metal like tin can be made to flow on a sloping surface.

Vapour phase refining is used for refining titanium metal. First metal is converted to volatile compound and collected. Next, it is then decomposed to give pure metal.

Let's analyze each ore to identify the metal and then its atomic number:

Sphalerite is primarily a zinc ore (its chemical formula is $\text{ZnS}$). Zinc has an atomic number of $30$.

Siderite is an ore of iron (its chemical formula is $\text{FeCO}_3$). Iron has an atomic number of $26$.

Malachite is a copper ore (its basic composition includes copper, as in $\text{Cu}_2\text{CO}_3(\text{OH})_2$). Copper has an atomic number of $29$.

Thus, the atomic numbers for metals $X, Y, Z$ (corresponding to sphalerite, siderite, and malachite) are:

$30, 26, 29$

So the correct answer is Option A.

Among the given equations, option (c) will give the required answer, i.e.,

$ (P)=\mathrm{Fe}_3 \mathrm{O}_4,(Q)=\mathrm{Fe},(R)=\mathrm{FeO}, $

i.e.

I. $3 \mathrm{Fe}_2 \mathrm{O}_3+\mathrm{CO} \longrightarrow 2 \mathrm{Fe}_3 \mathrm{O}_4+\mathrm{CO}_2$

II. $\mathrm{Fe}_3 \mathrm{O}_4+4 \mathrm{CO} \longrightarrow 3 \mathrm{Fe}+4 \mathrm{CO}_2$

III. $\mathrm{Fe}_2 \mathrm{O}_3+\mathrm{CO} \longrightarrow 2 \mathrm{FeO}+\mathrm{CO}_2$

Hence, option (c) is the correct answer.

Out of given four elements $\mathrm{C}, \mathrm{S}, \mathrm{Fe}$ and Au , the non-metals C and S exist in elemental form as allotropes. Au is a less active metal. It also exists in nature as elemental form, called nugget.

Fe is an electropositive metal. So, it exists in earth's crust in combined state (compounds),

e.g. $\mathrm{Fe}_2 \mathrm{O}_3, \mathrm{Fe}_3 \mathrm{O}_4, \mathrm{FeS}_2$ etc.

∵ Formula of given ores are as follows :

(A) Calamine $=\mathrm{ZnCO}_3$

(B) Chalcopyrite $=\mathrm{CuFeS}_2$

(C) Bauxite $=\mathrm{Al}_2 \mathrm{O}_3 \cdot 2 \mathrm{H}_2 \mathrm{O}$

(D) Haematite $=\mathrm{Fe}_2 \mathrm{O}_3$

Hence, option (a) is the correct answer, i.e.

Calamine $\left(\mathrm{ZnCO}_3\right)$ is the ore of zinc (Zn) and rest of all are ores of iron.

Hematite ( $\mathrm{Fe}_2 \mathrm{O}_3$ ), Magnetite ( $\mathrm{Fe}_3 \mathrm{O}_4$ ) Siderite $\left(\mathrm{FeCO}_3\right)$