General Principles And Processes Of Isolation Of Elements NEET PYQs (2005–2026) with Solutions

10 solved General Principles And Processes Of Isolation Of Elements PYQs

Real NEET and AIPMT questions from this chapter, newest first. Try each one, then open the answer and the step-by-step explanation.

1. Question 1 (NEET 2023)

   NEET 2023MediumIron Extraction

   The reaction that does NOT take place in a blast furnace between 900 K to 1500 K temperature range during extraction of iron is :

   1. AOption A: Fe₂O₃ + CO → 2FeO + CO₂
   2. BOption B: FeO + CO → Fe + CO₂
   3. COption C: C + CO₂ → 2CO
   4. DOption D: CaO + SiO₂ → CaSiO₃

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   Correct answer: (A) Fe₂O₃ + CO → 2FeO + CO₂

   Explanation

   In the blast furnace, Fe₂O₃ is first reduced to Fe₃O₄ and then to FeO before metallic iron is formed. The direct conversion: Fe₂O₃ + CO → 2FeO + CO₂ does not occur in the 900 K to 1500 K range as written. Other reactions listed are important processes in the blast furnace: - FeO is reduced to Fe by CO. - CO is regenerated by reaction of carbon with CO₂. - CaO reacts with SiO₂ impurity to form slag (CaSiO₃). Hence, option (A) is correct.

2. Question 2 (NEET 2022)

   NEET 2022MediumImportant Ores and Their Composition

   Match List-I with List-II. Choose the correct answer from the options given below:

   1. AOption A: (a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
   2. BOption B: (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
   3. COption C: (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)
   4. DOption D: (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)

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   Correct answer: (C) (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)

   Explanation

   Matching: Haematite → Fe₂O₃ (iii) Magnetite → Fe₃O₄ (i) Calamine → ZnCO₃ (ii) Kaolinite → Al₂(OH)₄Si₂O₅ (iv) Hence option (C) is correct.

3. Question 3 (NEET 2021)

   NEET 2021EasyBlast Furnace

   The maximum temperature that can be achieved in blast furnace is:

   1. AOption A: Upto 5000 K
   2. BOption B: Upto 1200 K
   3. COption C: Upto 2200 K
   4. DOption D: Upto 1900 K

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   Correct answer: (C) Upto 2200 K

   Explanation

   As per NCERT, the maximum temperature achieved in a blast furnace is approximately 2170 K, so the closest option is 2200 K.

4. Question 4 (NEET 2021)

   NEET 2021EasyRefining of Metals

   Which method is used to obtain highly pure metal which is liquid at room temperature?

   1. AOption A: Zone refining
   2. BOption B: Electrolysis
   3. COption C: Chromatography
   4. DOption D: Distillation

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   Correct answer: (D) Distillation

   Explanation

   Distillation is used for purification of low boiling metals like mercury.

5. Question 5 (NEET 2020)

   NEET 2020EasyMetallurgy and Refining of Metals

   Identify the correct statement from the following:

   1. AOption A: (1) Wrought iron is impure iron with 4% carbon.
   2. BOption B: (2) Blister copper has blistered appearance due to evolution of CO₂.
   3. COption C: (3) Vapour phase refining is carried out for Nickel by Van Arkel method.
   4. DOption D: (4) Pig iron can be moulded into a variety of shapes.

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   Correct answer: (D) (4) Pig iron can be moulded into a variety of shapes.

   Explanation

   Pig iron contains a high percentage of carbon and can be moulded into different shapes. Wrought iron contains very low carbon content, blister copper appearance is due to SO₂ evolution, and nickel is refined by Mond process, not Van Arkel method.

6. Question 6 (NEET 2019)

   NEET 2019EasyMetallurgy Terminology

   Identify the incorrect statement.

   1. AOption A: Gangue is an ore contaminated with undesired materials
   2. BOption B: The scientific and technological process used for isolation of the metal from its ore is known as metallurgy
   3. COption C: Minerals are naturally occurring chemical substances in the earth's crust
   4. DOption D: Ores are minerals that may contain a metal

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   Correct answer: (A) Gangue is an ore contaminated with undesired materials

   Explanation

   Gangue refers to the earthy and unwanted impurities associated with an ore, not the ore itself.

7. Question 7 (NEET 2018)

   NEET 2018MediumEllingham diagram

   Considering Ellingham diagram, which of the following metals can be used to reduce alumina?

   1. AOption A: Fe
   2. BOption B: Zn
   3. COption C: Cu
   4. DOption D: Mg

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   Correct answer: (D) Mg

   Explanation

   A metal more reactive than aluminium can reduce alumina. Magnesium is more reactive than aluminium and can reduce Al₂O₃. Hence, option (D) is correct.

8. Question 8 (NEET 2017)

   NEET 2017MediumLeaching and Extraction of Silver/Gold

   Extraction of gold and silver involves leaching with CN⁻ ion. Silver is later recovered by

   1. AOption A: Displacement with Zn
   2. BOption B: Liquation
   3. COption C: Distillation
   4. DOption D: Zone refining

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   Correct answer: (A) Displacement with Zn

   Explanation

   In cyanide leaching, silver forms soluble complex [Ag(CN)₂]⁻. Zinc, being more reactive, displaces silver: 2Na[Ag(CN)₂] + Zn → Na₂[Zn(CN)₄] + 2Ag↓

9. Question 9 (NEET 2016)

   NEET 2016EasyCorrosion and Galvanization

   Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because:

   1. AOption A: Zinc is lighter than iron
   2. BOption B: Zinc has lower melting point than iron
   3. COption C: Zinc has lower negative electrode potential than iron
   4. DOption D: Zinc has higher negative electrode potential than iron

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   Correct answer: (D) Zinc has higher negative electrode potential than iron

   Explanation

   Standard reduction potentials: $$E^\circ_{Zn^{2+}/Zn} = -0.76\ \text{V}$$ $$E^\circ_{Fe^{2+}/Fe} = -0.44\ \text{V}$$ Zinc has more negative electrode potential and oxidizes more easily. Thus zinc protects iron sacrificially. Hence option (D) is correct.

10. Question 10 (AIPMT 2015)

    AIPMT 2015EasyExtraction of Copper from Sulphide Ore

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

    1. AOption A: Copper(I) sulphide
    2. BOption B: Sulphur dioxide
    3. COption C: Iron(II) sulphide
    4. DOption D: Carbon monoxide

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    Correct answer: (A) Copper(I) sulphide

    Explanation

    During the extraction of copper from sulphide ores, cuprous oxide undergoes self-reduction with copper(I) sulphide: $$\mathrm{Cu_2S + 2Cu_2O \rightarrow 6Cu + SO_2\uparrow}$$ Thus copper(I) sulphide acts as the reducing agent and copper metal is obtained.