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NCERT Exemplar Class 12 Chemistry Chapter 6 Solutions: General Principles and Processes of Isolation of Elements

NCERT Exemplar Class 12 Chemistry Solutions Chapter 6 – General Principles and Processes of Isolation of Elements help you to revise the complete syllabus to score higher in CBSE Board exams. This chapter of NCERT Exemplar Class 12 Chemistry Solutions Chapter 6 – General Principles and Processes of Isolation of Elements covers all aspects of Isolation of Elements such as General Principles, Processes and their state of occurrence in nature.

NCERT exemplar solution will also help you to understand the extraction of metals, minerals, calculations, concentration, saturation, furnace, metal occurrence, ore, and purification. You will also understand the principles of oxidation and reduction that apply to extraction processes. Our subject matter experts have explained the solutions very clearly and included all the basic concepts/theories and rules of Chemistry.

NCERT Exemplar Class 12 Chemistry Solutions Chapter 6 – General Principles and Processes of Isolation of Elements has a total of 145 questions that are divided into 5 sections touching all the topics based on Chapter 6. The questions are of various kinds which will help you get a complete revision with the help of MCQ’S, short answer questions, fill in the blanks, true or false, numerical questions, worksheets and exercises to assist you in the preparation of class 12 and entrance examinations.

Important Topics for NCERT Exemplar Class 12 Chemistry Solutions Chapter 6 – General Principles and Processes of Isolation of Elements.

  1. The earth’s crust is the source of many elements. 70% of these elements are metals. Aluminium is the most common metal in the earth’s crust and iron is the second largest.
  2. The metals are found in two forms of nature: (i) native state (ii) combined state, depending on the chemical activity.
  3. Native state elements with low chemical reactions or precious metals with the lowest electropositive character are not attacked by oxygen, moisture and CO2 in the air, e.g., Ag, Pt, S, O, N, noble gases, etc.
  4. Combined states are highly reactive elements such as F, Si, Na, K, etc. in the form of their compounds such as oxide, carbonate sulfates, H, lids, and so on.
  5. Minerals and Ores: Minerals that are found naturally in the form of metals in the earth’s crust are called minerals. Not every mineral is suitable for extracting metals. Ore is a mineral that is economically and extracted conventionally. Thus, all ores are minerals but not all minerals are ions
  6. Gangue or Matrix: Ores along with impurities.
  7. Metallurgy: The entire scientific and technological process used to separate the metal from its ores is known as metallurgy.
  8. Various types of Metallurgical Processes:
  • Pyrometallurgy: The extraction of metals takes place at very high temperatures   E.g. Q, Fe, Zn, Sn, etc. 
  • Hydrometallurgical process: In this process, the metals are extracted using their water solution. Ag and Au are extracted using this method.
  • Electrometallurgical process: metals when extracted from their molten salt solution via the electrolytic method. For example, Na, K, Li, Ca, etc.
  1. Steps of Metallurgy:
  • Crushing of Ore:  Big lumps of ore crushed into smaller pieces (pulverization). 
  • The concentration of Ores: Removal of unwanted materials (eg sand, clay, etc.) is called ore density, ore dressing or ore dressing.
  • Hydraulic Washing/Gravity Separation/Levigation: The process of removing lighter earth pollutants from heavier ore particles by washing them with water is called levitation. 
  • Commonly methods for oxide ores: Hematite, tinstone and native ores of Au, Ag, etc.
  • Froth Floatation: This method is used for the concentration of sulfide ores. This method is based on the oil wetting of ore particles gangue by water. 
  • Activator: Activation of floating property of one component of the ore I and help in separation of minerals present in that same ore (CuSO4 is used as an activator). 
  • Depressants: These are used to prevent certain types of particles from dissolving in air, for example, NaCN can be used as a depressant in the separation of ZnS and PbS ores. 
  • Collectors: Raising the ore particles’ non-wet ability by water, e.g., pine oils, xanthenes, and fatty acids.
  1. Electromagnetic Separation: Method employed when either ore or impurities associated with metals are magnetic e.g., chromites, FeCr2O4.
  2. Electrostatic Separation: It is used in the electrostatic field to immediately separate the charged lead sulfide (good conductor) and it is thrown from the roller by the roller sulfide (weak conductor), which is not charged and, therefore, dried vertically from the roller.
  3. Chemical Method-Leaching: Leaching is a process in which the ore is concentrated by a chemical reaction with a suitable reagent that dissolves the ore but does not dissolve impurities.
  4. Extraction of Crude Metals from Concentrated Ore:  Dense ore is generally converted to oxide before reduction because oxide is easy to reduce.
  5. Concentrated ore involves two major steps
  • Oxide Conversion
  • Oxides reduction to metal
  1. Oxides conversion:
  • Calcination: This is the process of turning the ore into its oxides below its melting point, due to a strong supply of air, or a lack of air.
  • Roasting: This is the process of turning ore into its metallic oxide due to strong heating when it is below the melting point in the air.
  • Reduction of the Oxides to Metal: Roasted or calcined ore is reduced to free metal by reduction. 
  • Smelting: The process of dissolving an oxidized ore with carbon (C) or CO is called refining. (By reverberatory furnace).
  1. Occurrence and Extraction of Some Metals:
  • Metal Aluminium (AI) Occurrence 
  1. Bauxite – Al2O3.XH2O 2. 
  2. Cryolite – Na3AlF6

     Extraction method: Electrolysis of Al2O3 in dissolved molten state Na3A1F6 (neutral flux). 

  • Metal Iron (Fe) Occurrence:
  1. Hematite – Fe2O3
  2. Magnetite – FE3O4 

    Extraction method:  Oxide Reduction with CO and coke in the blast furnace.

  • Metal Copper (Cu) Occurrence:
  1. Copper pyrites – CuFeS2
  2. Copper glance – Cu2S

      Extraction method:  Partial Roasting of sulfide and reduction.

  • Metal Zinc (Zn) Occurrence :
  1. Zinc blende or sphalerite-ZnS
  2. Calamine – ZnCO3 3. Zincite – ZnO 

      Extraction method: Roasting followed by reduction with coke.

  • Metal Nickel (Ni) Occurrence:
  1. Pentlandite – (Ni, Cu, Fe) S 
  2. Kupfernickel – NiAs 3. Smaltite – (Fe, Co. Ni)

       Extraction method: Roasting followed by Refining is done by Mond’s Process.

Discussion of Exercises of NCERT Exemplar Class 12 Chemistry Solutions Chapter 6 – General Principles and Processes of Isolation of Elements.

  1. The first section of NCERT Exemplar Class 12 Chemistry Solutions Chapter 6 – General Principles and Processes of Isolation of Element has 26 questions which are MCQs that are based on the idea of the method of purification, extraction of chlorine from brine, Reverberatory furnace, and reactions of auto reduction method.
  2. The second section has 18 questions which are short answer type questions that will help you to understand different experiments and theories of extraction of chlorine, Ellingham diagram, Van Arkel Method, Froth Floatation Method and other metallurgical processes.
  3. The third section has 5 questions which are matching type questions that are a mixture of different terminologies based on isolation of elements and metal extraction from their ore.
  4. The fourth section has 5 questions which are matching type questions that are Assertion and Reason Type questions that are based on Hydrometallurgy and Zone refining method.
  5. The fifth section has only one question that is a long answer type which will ask you to explain reducing agent and oxides conversion processes.
  6. The NCERT exemplar questions include the simplest quality problems that will test you in varying levels of difficulty on any given topic. Questions that are mentioned within the NCERT exemplar are of immense importance from CBSE’s point of view.

Why Use NCERT Exemplar Class 12 Chemistry Solutions Chapter 6 – General Principles and Processes of Isolation of Elements by Instasolv?

  • NCERT Exemplar Class 12 Chemistry Solutions Chapter 6 – General Principles and Processes of Isolation of Elements by Instasolv expert incorporates all the significant subjects with point by point clarification that plans to assist students with understanding the ideas better. 
  • Experiencing the arrangements given above will assist you in knowing how to approach and take care of the tough questions asked during Board exams.