PYQSide ExamsMy practice

General Principles of Isolation of Elements · Question 14

AIPMT 2012 (Mains)MCQMedium📈 Topic in 0% papers+4−1
1

The Gibbs energy for the decomposition of Al2O3 at 500 is as follows 23Al2O3 43Al + O2 rG = +960 kJ mol-1 The potential difference needed for the electrolytic reduction of aluminium oxide (Al2O3) at 500 is at least

  1. 4.5 V
  2. 3.0 V
  3. 2.5 V
  4. 5.0 V

Answer

(3) 2.5 V

Solution

In 23Al2O3 43Al + O2, 43 mol of Al3+ is reduced:

n = 43 3 = 4 electrons

rG = -nFE ⇒ the minimum potential difference = rGnF

= 960 1034 96500

= 2.49 V 2.5 V

∴ As per NCERT, the potential difference needed for the electrolytic reduction of Al2O3 at 500 °C is at least 2.5 V.

Answer: (3)

AIPMT 2012 (Mains)

Keep practising — General Principles of Isolation of Elements

2

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

  1. carbon monoxide
  2. copper (I) sulphide
  3. sulphur dioxide
  4. iron (II) sulphide.
Out of syllabusAIPMT 2012 (Prelims)
3

Aluminium is extracted from alumina (Al2O3) by electrolysis of a molten mixture of

  1. Al2O3 + HF + NaAlF4
  2. Al2O3 + CaF2 + NaAlF4
  3. Al2O3 + Na3AlF6 + CaF2
  4. Al2O3 + KF + Na3AlF6
Out of syllabusAIPMT 2012 (Prelims)
4

Which one of the following is a mineral of iron?

  1. Malachite
  2. Cassiterite
  3. Pyrolusite
  4. Magnetite
Out of syllabusAIPMT 2012 (Prelims)
5

The following reactions take place in the blast furnace in the preparation of impure iron. Identify the reaction pertaining to the formation of the slag.

  1. Fe2O3(s) + 3CO(g) 2Fe(l) + 3CO2(g)
  2. CaCO3(s) CaO(s) + CO2(g)
  3. CaO(s) + SiO2(s) CaSiO3(s)
  4. 2C(s) + O2(g) 2CO(g)
Out of syllabusAIPMT 2011 (Mains)
6

Which of the following elements is present as the impurity to the maximum extent in pig iron?

  1. Manganese
  2. Carbon
  3. Silicon
  4. Phosphorus
Out of syllabusAIPMT 2011 (Prelims)
7

Which of the following pairs of metals is purified by van Arkel method?

  1. Ga and In
  2. Zr and Ti
  3. Ag and Au
  4. Ni and Fe
Out of syllabusAIPMT 2011 (Prelims)
8

Sulphide ores of metals are usually concentrated by froth flotation process. Which one of the following sulphide ores offers an exception and is concentrated by chemical leaching?

  1. Galena
  2. Copper pyrite
  3. Sphalerite
  4. Argentite
Out of syllabusAIPMT 2007
9

Which of the following statements about the advantage of roasting of sulphide ore before reduction is not true?

  1. The fG of the sulphide is greater than those for CS2 and H2S.
  2. The fG is negative for roasting of sulphide ore to oxide.
  3. Roasting of the sulphide to the oxide is thermodynamically feasible.
  4. Carbon and hydrogen are suitable reducing agents for metal sulphides.
Out of syllabusAIPMT 2007
10

The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is (Atomic mass : Al = 27)

  1. 270 kg
  2. 540 kg
  3. 90 kg
  4. 180 kg
AIPMT 2005
11

The method of zone refining of metals is based on the principle of

  1. greater mobility of the pure metal than that of the impurity
  2. higher melting point of the impurity than that of the pure metal
  3. greater noble character of the solid metal than that of the impurity
  4. greater solubility of the impurity in the molten state than in the solid
Out of syllabusAIPMT 2003

All General Principles of Isolation of Elements PYQs →

PDFDownload General Principles of Isolation of Elements PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All NEET Chemistry chapters
Physical ChemistrySome Basic Concepts of ChemistryStructure of AtomStates of MatterThermodynamicsEquilibriumRedox ReactionsSolid StateSolutionsElectrochemistryChemical KineticsSurface Chemistry
Inorganic ChemistryClassification of Elements and Periodicity in PropertiesChemical Bonding and Molecular StructureHydrogens-Block Elementsp-Block Elements (Group 13 & 14)Environmental ChemistryGeneral Principles of Isolation of Elementsp-Block Elements (Group 15–18)d- and f-Block ElementsCoordination Compounds
Organic ChemistryOrganic Chemistry – Some Basic Principles and TechniquesIsomerismHydrocarbonsHaloalkanes and HaloarenesAlcohols, Phenols and EthersAldehydes, Ketones and Carboxylic AcidsAminesBiomoleculesPolymersChemistry in Everyday LifePrinciples Related to Practical Chemistry