JEE Advanced · Chemistry · 20. Metallurgy

Paragraph:
Copper is the most noble of the first row transition metals and occurs in small deposits in several countries. Ores of copper include chalcanthite $\left(\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}\right)$, atacamite $\left(\mathrm{Cu}_2 \mathrm{Cl}(\mathrm{OH})_3\right)$, cuprite $\left(\mathrm{Cu}_2 \mathrm{O}\right)$, copper glance $\left(\mathrm{Cu}_2 \mathrm{~S}\right)$ and malachite $\left(\mathrm{Cu}_2(\mathrm{OH})_2 \mathrm{CO}_3\right)$. However, 80\% of the world copper production comes from the ore chalcopyrite $\left(\mathrm{CuFeS}_2\right)$. The extraction of copper from chalcopyrite involves partial roasting, removal of iron and self-reduction.
Question:
Iron is removed from chalcopyrite as

A $\mathrm{FeO}$
B $\mathrm{FeS}$
C $\mathrm{Fe}_2 \mathrm{O}_3$
D $\mathrm{FeSiO}_3$

Verified Solution

Answer & Solution

Correct Answer

(D) $\mathrm{FeSiO}_3$

Step-by-step Solution

Detailed explanation

Iron is removed in the form of slag of $\mathrm{FeSiO}_3$

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match the compounds in LIST-

I

with the observations in LIST-

II

, and choose the correct option.

	LIST- $I$		LIST- $II$
$(I)$	Aniline	$(P)$	Sodium fusion extract of the compound on boiling with ${FeSO}_{4}$ , followed by acidification with conc. $H_{2} {SO}_{4}$ , gives Prussian blue color.
$(II)$	$o -$ Cresol	$(Q)$	Sodium fusion extract of the compound on treatment with sodium nitroprusside gives blood red color.
$(III)$	Cysteine	$(R)$	Addition of the compound to a saturated solution of ${NaHCO}_{3}$ results in effervescence.
$(IV)$	Caprolactam	$(S)$	The compound reacts with bromine water to give a white precipitate.
		$(T)$	Treating the compound with neutral ${FeCl}_{3}$ solution produces violet color.

JEE Advanced 2022 Hard

A sample $(5.6 \mathrm{~g})$ containing iron is completely dissolved in cold dilute $\mathrm{HCl}$ to prepare a $250 \mathrm{~mL}$ of solution. Titration of $25.0 \mathrm{~mL}$ of this solution requires $12.5 \mathrm{~mL}$ of $0.03 \mathrm{M} \mathrm{KMnO}_{4}$ solution to reach the end point. Number of moles of $\mathrm{Fe}^{2+}$ present in $250 \mathrm{~mL}$ solution is $\mathbf{x} \times 10^{-2}$ (consider complete dissolution of $\mathrm{FeCl}_{2}$ ). The amount of iron present in the sample is $\mathbf{y} \%$ by weight.
(Assume: $\mathrm{KMnO}_{4}$ reacts only with $\mathrm{Fe}^{2+}$ in the solution Use: Molar mass of iron as $56 \mathrm{~g} \mathrm{~mol}^{-1}$ )
The value of $y$ is________ .

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Match the following

Column I	Column II
(A) $CH _3- CHBr - CD _3$ on treatment with alc. KOH gives $CH _2= CH - CD _3$ as a major product.	(P) E1 reaction
(B) $Ph - CHBr - CH _3$ reacts faster than $Ph - CHBr - CD _3$	(Q) E2 reaction
(C) $Ph - CH _2- CH _2 Br$ on treatment with $C _2 H _5 OD / C _2 H _5 O ^{-}$gives $Ph - CD = CH _2$ as the major product	(R) El cb reaction
(D) $PhCH _2 CH _2 Br$ and $PhCH _2 CH _2 Br$ react with same rate	(S) First order reaction

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List - i	List - II
A. Alpha decay	P. ${ }_8^{15} O \rightarrow{ }_7^{15} N+\ldots \ldots \ldots$.
B. $\beta^{+}$decay	Q. ${ }_{92}^{238} U \rightarrow{ }_{90}^{234} Th +\ldots \ldots \ldots$.
C. Fission	R. ${ }_{83}^{185} Bi \rightarrow{ }_{82}^{184} Pb+\ldots \ldots \ldots$.
D. Proton emission	S. ${ }_{94}^{239} Pu \rightarrow{ }_{57}^{140} La +\ldots \ldots \ldots$.

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Column I	Column II
(A) \(CH _3- CHBr - CD _3\) on treatment with alc. KOH gives \(CH _2= CH - CD _3\) as a major product.	(P) E1 reaction
(B) \(Ph - CHBr - CH _3\) reacts faster than \(Ph - CHBr - CD _3\)	(Q) E2 reaction
(C) \(Ph - CH _2- CH _2 Br\) on treatment with \(C _2 H _5 OD / C _2 H _5 O ^{-}\)gives \(Ph - CD = CH _2\) as the major product	(R) El cb reaction
(D) \(PhCH _2 CH _2 Br\) and \(PhCH _2 CH _2 Br\) react with same rate	(S) First order reaction