JEE Advanced (One or More Correct Option): General Principles & Process of Isolation of Metals | Chapter-wise Tests for JEE Main & Advanced PDF Download

Q.1. The chief reaction(s) occurring in blast furnace during extraction of iron from haematite is/are:
(a) Fe₂O₃ + 3CO → 2Fe + 3CO₂
(b) FeO + SiO₂ → FeSiO₃
(c) Fe₂O₃ + C → 2Fe + 3CO
(d) CaO + SiO₂ → CaSiO₃

Correct Answer is option (a and d)
In extraction of Fe, Fe₂O₃ is primary reduced by CO below 710°C and acidic impurity of SiO₂ is removed in the form of CaSiO₃ (slag).

Q.2. Which of the following will respond positively to the chromyl chloride test?
(a) CuCl₂
(b) ZnCl₂
(c) HgCl₂
(d) AgCl

Correct Answer is option (c and d)
HgCl₂ and AgCl are covalent in nature and insoluble in H₂O.

Q.3. K₄[Fe(CN)₆] is used for the detection of
(a) Fe²⁺
(b) Fe³⁺
(c) Cu²⁺
(d) Zn²⁺

Correct Answer is option (b, c and d)
Fe³⁺ → Fe₄ [Fe(CN)₆]₃ Prussian blue
Cu²⁺ → Cu₂ [Fe (CN)₆] Reddish brown
Zn²⁺ → Zn₂ [Fe (CN)₆] Bluish white

Q.4. Which of the following does not respond to chromyl chloride test?
(a) NH₄Cl
(b) KCl
(c) HgCl₂
(d) SnCl₄

Correct Answer is option (c and d)
Covalent chlorides do not respond to chromyl chloride test, e.g., SnCl₄, HgCl₂

Q.5. Which of the following oxides dissolve in sodium hydroxide forming corresponding salts.
(a) Al₂O₃ 
(b) ZnO
(c) SnO₂ 
(d) PbO₂

Correct Answer is option (a, b, c and d)
AI₂O₃ + 2NaOH → 2NaAlO₂ + H₂O
ZnO + 2NaOH → Na₂ZnO₂ + H₂O
SnO₂ + 2NaOH → Na₃SnO₃ + H₂O
PbO₂ + 2NaOH → Na₂PbO₃ + H₂O

Q.6. In which of the following pairs, the minerals are converting into metals by self-reduction?
(a) Ag₂ S, ZnS
(b) Cu₂ S, HgS
(c) PbS, ZnS
(d) Cu₂ S, PbS

Correct Answer is option (b and d)
Cu₂S + 2Cu₂O → 5Cu + SO₂
HgS + 2HgO → 3Hg + SO₂
PbS + 2PbO → 3Pb + SO₂

Q.7. Which of the following is/are applicable for the basic furnace lining in steel manufacture?
(a) Basic lining involve the presence of SiO₂
(b) Basic lining involve the presence of CuO
(c) Basic lining involve the presence of MgO
(d) basic linings are used to remove the acidic impurities like P₄O₁₀, SO₂, etc

Correct Answer is option (b, c and d)
6CaO + P₄O₁₀ → 2Ca₃(PO₄)₂;
MgO + SO₂ → MgSO₃

Q.8. Roasting of copper pyrites is done
(a) to remove moisture.
(b) to oxidize free sulphur
(c) to decompose sulphides into oxides.
(d) to remove volatile organic impurities

Correct Answer is option (a, b, c and d)
The concentrated are (Copper Pyrite) is roasted in a furnace in presence of air current. During this process, sulphur is oxidized to SO₂, volatile organic impurities are removed, moisture is removed and sulphides decompose to give oxides.
2Cu FeS₂ + O₂ → Cu₂S + 2 FeS + SO₂
S + O₂ → SO₂

Q.9. Extraction of gold is done by the following process
Au + CN^– → (X)
(X) + Zn → (Y) + Au↓
Incorrect (X) and (Y) are
(a) [Au(CN)₂]^–, [Zn(CN)₄]^2–
(b) [Au(CN)₂]^–, [Zn(CN)₆]^4–
(c) [Au(CN)₄]^3–, [Zn(CN)₂]
(d) [Au(CN)₄]^–, [Zn(CN)₄]^–

Correct Answer is option (b, c and d)
Extraction of gold is done by the following process:
4Au + 8CN^- + 2H₂O + O₂ → 4[Au(CN)₂]^- + 4OH^-
2[Au(CN)₂]^– + Zn → [Zn(CN)₄]^2– + 2Au↓

Q.10. Find out the incorrect statement.
(a) In the extraction metallurgy of copper silica removes Fe₂O₃ present in the matte by forming FeSiO₃ 
(b) Cast iron has lower carbon content than pig iron
(c) Out of carbon & carbon monoxide (CO), CO is a better reducing agent than carbon for ZnO
(d) Cryolite is used in the extractive metallurgy of aluminum only to lower the melting point of the mixture.

Correct Answer is option (a, b and d)
Carbon is a better reducing agent than CO for reduction of zinc oxide.