Copper pyrites It has lower levels of carbon in it (3%). 2Fe + O2 → 2FeO, Answer the following : Delhi 2012) Answer: (c) What is the role of depressants in the froth floatation process? can be purified by this process. Example : In refining of Cu At anode : (oxidation) Write the principles of the following methods : (ii) Chromatographic method : It is based on the principle that different components of a mixture are differently adsorbed on the adsorbent. Chromatography is a widely used process for separation, purification, identification and characterization of the different components of a mixture which are differently adsorbed on a suitable adsorbent. Question 26. Delhi 2014) (i) Preparation of cast iron from pig iron : Cast iron is made by melting pig iron with scrap iron and coke using hot air blast. The powdered bauxite ore is heated with cone. (ii) Titanium (Comptt. Answer: Cu2+ + 2e– → Cu. As a result, pure metal crystallizes out of the melt and the impurities pass to the adjacent molten zone. (i) Recovery of silver from the solution obtained by leaching silver ore with a solution of NaCN. Question 30. What is the role of CO2 in the extractive metallurgy of aluminium from its ore? Write down the reactions taking place in different zones in the blast furnace during the extraction of iron. Explain: (i) Zone refining (ii) Column chromatography. Whereas, ∆fG of Cu2O is larger than carbon monoxide’s , thus C can reduce copper (I) oxide to copper.Therefore, it is more difficult to extract copper from pyrites than it is to extract from its oxide. Q7. This is a very useful method of purifying elements present in minute amounts. Thereby, different elements have different movement speed through the phase , because of which they can be separated from each other. 6CaO + P4O10 → 2Ca2 (P04)2 Slag (i) NaCN acts as a leaching agent or oxidising agent, thus oxidises Ag to Ag+ which then combines with CN– ions to form respective soluble complex. Likewise, it isn’t possible for Zn to reduce MgO but Mg can reduce ZnO to Zn. The component which is more strongly adsorbed by the adsorbent takes a greater amount of time to move through it than the component that is weakly adsorbed. This would have resulted in the wastage of aluminium and as graphite is cheaper than aluminum it is expendable.This is the role of aluminum. Question 45. Silicon, boron, , gallium etc. The carbonyl is subjected to higher temperature so that it is decomposed giving the pure metal, Ni(CO) 4 → 450 – 470 K Ni + 4CO The mixture is put in a liquid or gaseous medium which is moved through the adsorbent. SiO2 and FeO forms FeSiO3 ( slag )which floats on the molten matter.FeO + SiO2 ⇒ FeSiO3 (slag). Kwaliteit catering in Nederland bestellen doet u bij Kerstdiner, dé cateraar bij u in de buurt! (ii) Electrolytic refining of metals : Here the impure metal is made to act as anode and a strip of the same metal in pure form is used as cathode. All India 2012) (b) What is the role of cryolite in the extraction of aluminium? This is repeated over several times, causing the segregation of impurities at one end of the bar. Zoomalia.com, il negozio di animali online al miglior prezzo. Outline the principles behind the refining of metals by the following methods : Mond process is used for refining of nickel metal. (ii) Role of silica in the metallurgy of copper Q2. Pig iron is the iron obtained from blast furnace. Ore: The mineral from which metal can be extracted conveniently and economically is called an ore. Hence, these minerals qualify as ores of zinc. Het laatste nieuws over de beurs, financiële wereld, economie, politiek en ondernemen vind je op fd.nl (iii) What is meant by the term ‘chromatography’? The requirements are. Silicon, boron, , gallium etc. Question 64. This Chapter is planned, organized and described by Dr. T K Bansal for blind and visually impaired students. (a) Which of the following ores can be concentrated by froth floatation method and why? A column of adsorbent e.g. (iii) Lowering down the melting point and increasing the conductivity. 2FeS + 3O2 → 2FeO + 2SO2 The silica is used to remove ferrous oxide and ferrous sulphide as slag. Answer: Question 61. Answer: Question 4. Solutions provided with brief explanation for all the questions. Answer: Froth floatation method : This method is used for removing gangue from sulphide ores. Copper pyrites Cu2+ + 2e– → Cu. Question 16. Write the principle behind the following methods of refining : (ii) Vapour phase refining of metals (Comptt. (i) Pig iron into steel : For this Basic Oxygen Process (BOP) is used. Answer: Chapter 06: General Principles and Processes of Isolation of Elements of Chemistry Examplar Problems book - I. This process is repeated several times which leads to the segregation of impurities at one end of the rod. (Delhi 2013) As a result, pure metal crystallizes out of the melt and the impurities pass to the adjacent molten zone. (Comptt. (i) NaCN in the extraction of silver from a silver ore. (a) The 0.5% solution of sodium or potassium cyanide is used for the leaching of silver metal. Boron, silicon, gallium etc. BYJU’S provides NCERT notes, books, sample papers, previous year question papers, study materials, important questions, exercises, worksheets and assignments to help you in knowing concepts of metallurgy. Cryolite makes alumina a good conductor of electricity. The CO2 formed near upper layers reacts with the coke which reduces it into CO. Thus, at a temperature beyond 1350°C, Al can reduce MgO. (ii) Zone refining 2FeO + Si → 2Fe + SiO2, Kontakt Amsterdamer Str. It has slightly lower carbon content (about 3%) and is extremely hard and brittle. (Comptt. Name an element which is refined by this method. How is leaching carried out in case of low grade copper ores? Predict conditions under which Al might be expected to reduce MgO. Af cathode : (reduction) (ii) Electrolytic refining of metals: Here the impure metal is made to act as anode and a strip of the same metal in pure form is used as cathode. Out of C and CO, which is a better reducing agent for ZnO ? (i) Vapour phase refining of titanium metal 2Na [ Al ( OH)4 ](aq) + CO2 ⇒ Al2O3.xH2O(s) + 2NaHCO3(aq)hydrated alumina This process is repeated several times which leads to the segregation of impurities at one end of the rod. Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction? Al2O3.xH2O(s) ⇒ Al2O3(s) + xH2O( g) [1470 k]. (ii) Germanium: Zone refining. As the circular heater moves, the impurities move into the adjacent molten zone and the pure metal crystallizes out. At cathode : (reduction) (i) Vapour phase refining On passing the electric current the metal ions from the electrolyte collect at the cathode as pure metal and the impure metal of the anode dissolves into the solution ( electrolyte ) in the form of ions. 2ZnS + 3O2 → 2ZnO + 2SO2 ↑ (i) using collectors. Question 82. Then the end with impurities is cut off. ... Write two basic requirements for refining of metal by Mond process and by Van Arkel Method. (d) Converted into a chloro complex of Hg Oxidation involves [NCERT 1971, 81; CPMT 1980, 82, 83; 18. Answer: Cu → Cu2+ + 2e– and froth stabilisers (e.g., cresols, aniline) which enhance non-wettability of the mineral particles and froth stabilisation respectively. (ii) The melting point of alumina is very high. NaOH to remove impurities of Fe2O3, SiO, and TiO2. (iii) Cryolite in the metallurgy of aluminium (All India 2010) 2C + O2 → 2CO, What is the function of SiO2 in the metallurgy of copper? (i) Froth floatation method : This method is used for removing gangue from sulphide ores. (All India 2013) cresols, aniline) which enhance non-wettability of the mineral particles and froth stabilisation respectively. In this process fused mixture of CaCl2 and NaCl is electrolyzed at 873 K. Sodium is obtained the cathode and Cl2 is discharged at the anode. (i) Zone refining Complex formed in the following methods are (I) Mond's process for purification of nickel (II) Removal of lead poisoning from the body (III) Cyanide process for extraction of silver (IV) Froth flotation process for separation of `ZnS` from galena ore by using depresent. (Comptt. Delhi 2012) All India 2012) All India 2013) At anode : (oxidation) Answer: Principles Isolation of Elements is one of the interesting topics. All India 2014) It is used for concen­tration of sulphide ores. (iii) Silica in the extraction of copper. (i) Zone refining of metals: This method is based on the principle that impurities are more soluble in the molten state of the metal (the melt) than in the solid state. Students can also obtain in depth knowledge about the reactions involved in metal extraction. Q25. Example : In case of an ore containing ZnS and PbS, the depressant used is NaCN. Role : Collectors e.g. As a result of which ore comes with froth and gangue remain in the solution. ‘. State the role of silica in the metallurgy of copper. The principle behind the chromatography is that different components of a mixture are differently adsorbed on an adsorbent. (i) SiO2 in the extraction of copper from copper matte (ii) Zinc oxide into metallic zinc. Q20. Describe how the following changes are brought about: Chromatographic method; The principle of this method is that different components of a mixture are differently adsorbed on an adsorbent. Describe the role of the following : Gratis auch mit Handy und Tablet . (Comptt. Answer: pine oils, fatty acids etc. What types of metals are usually purified by the method of zone refining? Question 75. (Delhi 2009) (All India 2016) Wenn die Augen brennen und jucken:Trockenheit kann viele Ursachen haben. Outline the principles of refining of metals by the following methods : The choice of a reducing agent in a particular case depends on thermodynamic factor. Which methods are usually employed for purifying the following metals : Question 53. When they both are put in suitable electrolyte containing soluble salt of same metal, the more basic metal remains in the solution and the less basic ones go to the anode mud. Answer: This process is repeated several times which leads to the segregation of impurities at one end of the rod. As the heater moves, the molten zone of the mod also moves along with it. The stability of the colloidal solution is because of solvation and the presence of charge on the dispersed phase particles. Now, to neutralize the aluminate present in the solution, carbon dioxide gas is passed through the solution we obtained. are purified this way. As the heater moves, the molten zone of the mod also moves along with it. Chapter 6 of NCERT Solutions for Class 12 Chemistry deals with the technological and scientific procedure for the isolation of metals from its ores. (iii) Limestone decomposes in the blast fumance into CaO and CO2 where CaO acts as basic flux which combines with acidic impurities of the ore like silica i.e., SiO2 to form calcium silicate in the form of slag. readily change into vapours leaving behind impurities which further get collected in receivers and upon cooling, pure metal is obtained. (i) Roasting: The process of heating strongly the concentrated sulphide ore in the presence of air is called roasting : In this powdered ore is mixed with collectors (e.g. Therefore, the crude metal is […] Describe the underlying principle of each of the following metal refining methods : (All India 2009) (i) Cryolite in the electrolytic reduction of alumina. What is the role of graphite rod in the electrometallurgy of aluminium? Question 68. Nickel is heated in a stream of carbon monoxide forming a volatile complex, nickel tetracarbonyl, Ni + 4CO → 330 – 350 K Ni(CO) 4. Give reasons for the following : (a) What is the principle behind ‘zone refining’ of metals? In this powdered ore is mixed with collectors (e.g. How is copper extracted from a low grade ore of it? The O2 penetrates through the metal and oxidises the impurities rapidly Question 44. (i) NaCN acts as a leaching agent or oxidising agent, thus oxidises Ag to Ag+ which then combines with CN– ions to form respective soluble complex. As the heater moves, the molten zone of the mod also moves along with it. (i) Silicon of high purity can be obtained by zone refining. When a hot air blast is blown through molten matte taken in a silica lined converter, FeS is oxidised to FeO. (i) Mond process (ii) van Arkel method (i) Nickel: Mond process (ii) During roasting copper pyrites are converted into a mixture of FeO and CuzO. Question 57. Answer: (a) Giving examples differentiate between calcination and roasting. When all of the iron has been removed as slag Cu2S is oxidized to Cu2O which then undergoes a reaction with Cu2S to give copper metal. Answer: (b) (i) Ni (ii) Ti/Zr Mineral: The naturally occuring chemical substances in form of which the metals occur in the earth along with impurities are called minerals. (Delhi 2012) Nickel is heated in a stream of carbon monoxide forming a volatile complex, nickel tetracarbonyl which is further subjected to higher temperature so that it is decomposed to give pure nickel. (All India 2012) (i) Zone refining method Answer: (i) NaCN acts as a leaching agent or oxidising agent, thus oxidises Ag to Ag+ which then combines with CN– ions to form respective soluble complex As sulphide ores are wetted with pine oil and their particles come up along with froth, while their gangue (impurities) particles are wetted with water so such particles settle down. Copper matte chiefly consists of Cuprous Sulphide (Cu2S) and some uncharged Ferrous Sulphide (FeS). Electrolytic refining of copper metal. Example : In refining of Cu At anode : (oxidation) In the process of zone refining, a circular mobile heater is fixed at one end of a rod of impure metal. (b) Write the role of dilute NaCN in the extraction of silver. (i) Vapour phase refining of metals : Flere the impure metal is converted into its volatile compound and collected elsewhere which is then decomposed by heating at a higher temperature to give pure metal. (ii) Electrolytic refining (ii) Depressants prevent the formation of froth with air bubbles of other sulphide ore. Q9. To master Class 12 chemistry one must solve the NCERT questions provided at the end of each chapter. The Mond process is used for the Option 1)purification of NiOption 2)extraction of MoOption 3)purification of Zr and TiOption 4)extraction of Zn Question 84. Alternatively,2Al + (3/2)O2 ⇒ Al2O3, Subtracting equation (ii) from (i) , we have NCERT Solutions for Class 12 Chemistry Chapter 6 General Principles and Processes of Isolation of Elements is the most important resource material that you need to prepare well for the CBSE Class 12 chemistry examination and competitive examinations. Delhi 2013) The following oxidations occur in different zones of furnace : CO2 (g) + C(s) → 2CO (g) (i) Name the method of refining to obtain silicon of high purity. (i) The role of cryolite (Na3AlF6) is to lower the melting point of the mixture and bring conductivity. Answer: (ii) Carbon monoxide in the purification of nickel. Question 78. However, the Gibbs free energy of formation of CO2 from CO is greater than the Gibbs free energy of formation of ZnO. Question 12. 2ZnS + 302 \(\stackrel{\Delta}{\longrightarrow}\) 2ZnO + 2S02. (i) Name the method of refining of metals such as Germanium. Extraction of iron from iron ore in different zones of blast furnace : Q16. (i) Preparation of cast iron from pig iron. The complex then heated to a higher temperature (450-470K) when it undergoes thermal decomposition giving pure nickel. This is then poured onto the top of the column. Answer: The ZnO is made into brickettes with coke and clay and heated above 673 K so that the reduction process goes to completion. The choice of stationary phase is done in a way that the elements of the mixture have different solubility in the phase. (ii) What is the role of SiOz in the extraction of copper? Zone refining: It is based on the principle that the impurities are more soluble in molten state than in the solid state of the metal. Answer: Question 66. This FeO combines with SiO2 (silica) to produce FeSiO3 (slag). Here the metal is converted into its volatile compound and collected elsewhere which on strong heating is decomposed to give pure metal. State the principle of the method of zone refining of metals. It is 4% carbon and contains many other impurities like Si, P, S, Mn in lesser amounts. • the volatile compound should be easily decomposable so that recovery is easy. Describe the role of As a result of which ore comes with froth and gangue remain in the solution. (iii) The iodine is used in refining of zirconium to form a volatile iodide which on decomposition at high temperature gives pure metal. (a) Zone refining of metals: This method is based on the principle that impurities are more soluble in the molten state of the metal (the melt) than in the solid state. Write the reactions taking place in different zones of the blast furnace to obtain Iron. Homepage der Universitätsbibliothek Paderborn. Name the principal ore of aluminium. (b) Column chromatography: Answer: (Comptt. It is the refining of impure metals using electricity. What is the name of this process? Pig iron differs from cast iron with respect to the carbon contents. After filteration of impurities sod. In this method, impure zinc becomes the anode while the cathode is a pure copper strip. (iii) Vapour phase refining : Pure metal forms volatile compound with suitable reagent and the volatile compound is decomposed to give pure metal. (iii) Upper zone (zone of reduction): Temperature 500 – 900 K. All India 2015) Describe the principle controlling each of the following processes : (ii) Electrolytic refining of metals (All India 2011) Answer: Question 46. (i) Zone refining of metals In this powdered ore is mixed with collectors (e.g., pine oils, fatty acids, etc.) Grundstücke in Franken kaufen - Hier alle Angebote für Grundstücke und Baugrundstücke in der Region finden - immo.inFranken.de. Answer: The subject matter experts create the solutions with the aim of helping students to score well in the board exams. can be purified by this process. Mond’s process is used for refining of nickel. (iii) Chromatography (Delhi 2016) (Comptt. Why is copper matte put in silica lined converter? Firstly, to remove the impurities of the ore, zinc blende is crushed and concentration is done by froth floatation. Boron, silicon, gallium etc. This was brief on Principles Isolation of Elements. (Comptt. (i) Zone refining is used for refining of Germanium. What is meant by the term ‘pyrometallurgy’? 2CuFeS2 + O2 \(\stackrel{\Delta}{\longrightarrow}\) Cu2S + 2FeS + SO2 (iii) Coke i.e., CO acts as a reducing agent in the extraction of iron from its oxides in the zone of reduction in blast fumance at 1123 K. Answer: Firstly, a concentrated NaOH solution is used to digest the powdered ore at 473 − 523 K and at a pressure of 35 − 36 bar. Out of C and CO, which is a better reducing agent at 673 K ? (a) Mond's process includes conversion of Ni to Ni (CO)4, and then decomposition of (b) van Arkel method includes conversion of Zr to volatile and then decomposition of , to Zr and . Here the impure metal is made to act as anode and a strip of the pure metal is used as cathode. e.g. In this reaction Au+ ions are reduced to Au. (i) using collectors. Question 63. Q8. 2CU2S + 3O2 → 2CU2O + 2SO2 (b) Wrought iron is the purest form of commercial iron which contains about 0.2 – 0.5% carbon while steel contains about (0.5 – 1.5)% carbon. Answer: (ii) Zone refining K, Ca , etc. (iii) Electrolysis (Comptt. We can see from this graph that if ∆fGθ of a metal’s oxide is more negative than another metal’s oxide, then the former metal can reduce the oxide of the latter metal ( i.e., the oxide with less negative ∆fGθ ). 2FeS + 3O2 ⇒ 2FeO + 2SO2FeO + SiO2 ⇒ FeSiO3. (ii) Vapour phase refining : Here the metal is converted into its volatile compound and collected elsewhere which then decomposed to give pure metal. Which reducing agent is employed to get copper from the leached low grade copper ore? (Delhi 2016) Nickel, zirconium and titanium are refined using this method. It is leached out using add or bacteria. Question 83. (iii) Depressants prevent the formation of froth with air bubbles of other sulphide ore. (b) NaCN in the extraction of silver from silver ore. (Comptt. This concept follows the principle various components of a mixture are adsorbed to different extents on an adsorbent. Question 36. Expatica is the international community’s online home away from home. The various steps involved in zinc extraction are : (1) Concentration of ore Unit 6 - General Principles and Processes of Isolation of Elements NCERT Class 12 Chemistry Text Book for Blind and Visually Impaired Students by Dr T K Bansal. (Comptt. (i) Zone refining of metals: This method is based on the principle that impurities are more soluble in the molten state of the metal (the melt) than in the solid state. (Comptt Delhi 2016) (All India 2012) In the electrometallurgy of aluminum, the anode is graphite and the cathode iron is graphite lined .The O2 being liberated due to electrolysis reacts with the graphite anode to liberate CO2 and CO. Had it been any other metal besides graphite, the oxygen would have reacted with the aluminum during the electrolysis to form Al2O3. enhance non-wettability of the mineral particles. Minerals are naturally available substances having metals or their compounds. Bahxite (Al2O3,2H2O) is the principal ore of aluminium. (i) Zone refining of metals : It is based on the principle that the impurities are more soluble in melt than in the solid state of the metal. Name the methods used for refining of following metals : The solution of sodium meta-aluminate is neutralized by passing CO2 when hydrated alumina separates out while sodium silicate remains in the solution. Name the method that is used for refining of nickel. (b) Out of PbS and PbCO3 (ores of lead), which one is concentrated by froth floatation process preferably? Write the principles of the following methods: Question 19. (in) What is the role of coke in the extraction of » iron from its oxides? Here limestone (CaCO3) decomposes into CaO and CO2. Write chemical equations for the involved reactions. Delhi 2013) (All India 2014) ZnO(s) + C(s) → Zn(s) + CO(g) (iii) The term chromatography was originally derived from the Greek word ‘chroma’ meaning colour and ‘graphy’ meaning writing because the method was first used for the separation of coloured substances into individual components. Copper matte has Cu2S and some FeS. At cathode : (reduction) ZnO is reduced to Zn at around 1673 K. From the figure below, we can observe that beyond 1073 K the Gibbs free energy of formation of CO from C and beyond 1273 K, the Gibbs free energy of formation of CO2 from C is smaller than the Gibbs free energy of formation of ZnO. (b) NaCN acts as a leaching agent or oxidising agent, thus oxidises Ag to Ag+ which then combines with CN– ions to form respective soluble complex. Describe the principle controlling each of the following processes : Silicon, boron, , gallium etc. Delhi 2014) (b) Write the name of the metal refined by each of the following processes : eblogx.com ist Teilnehmer des Partnerprogramms von Amazon Europe S.à r.l., ein Partnerwerbeprogramm, das für Websites konzipiert wurde, mittels dessen durch die Platzierung von dieser Werbeanzeige zu amazon.de Werbekostenerstattungen verdient werden können. Om aan te melden op My Account en alle functionaliteiten zonder problemen te gebruiken, moet je cookies accepteren.cookies accepteren. Magnetite (Fe3O4) → an ore of iron. Write the principle behind the froth floatation process. (Comptt. Answer: (ii) Lead can be refined by liquation. This method is based on the principle that “the impurities are more soluble in the molten than in the solid state of the metal.”, Question 41. Answer: (b) PbS (Lead sulphide) is concentrated by froth floatation process. In the process of zone refining, a circular mobile heater is fixed at one end of a rod of impure metal. Question 54. 192, 50735 Köln Telefon 0221 - 224 2541 [email protected] Für individuelle, konkrete Fragen zu den einzelnen Reisen wenden Sie … (i) Principle of Distillation : The impure metal is evaporated to obtain the pure metal as distillate. Het laatste nieuws over de beurs, financiële wereld, economie, politiek en ondernemen vind je op fd.nl The metals having low boiling points (Bi, Hg, Cd etc.) How can you separate alumina from silica in a bauxite ore associated with silica? CaCO3(s) → CaO(s) + CO2(g) Klick hier für GEILE HAUSRAUEN Pornos kostenlos . (ii) Liquation (Comptt. To remove basic FeO, an acidic flux silica is added during smelting. All efforts have been made to make the chapter fully accessible by providing headings, - describing figures Example : In refining of Cu At anode : (oxidation) Separation of alumina from silica in bauxite ore associated with silica is as follows : For example, carbonates of Ca, Mg, Zn are turned into their respective oxides through this process.ZnCO3 ZnO + CO2, Roasting is the conversion of sulfide ores into their metallic oxides by heating at a temperature below their melting points in excess presence of air. Assertion (A): Nickel can be purified by Mond’s process. A must-read for English-speaking expatriates and internationals across Europe, Expatica provides a tailored local news service and essential information on living, working, and moving to your country of choice. (Comptt. (iii) Vapour phase refining. Q4. (i) Hydraulic washing Also access the PDF version and download the same. Tetracarboxyl nickel (volatile) 450-470 K High temperature Decomposed. warning Report Error Answer: (Delhi 2014) In the process of zone refining, a circular mobile heater is fixed at one end of a rod of impure metal. Question 28. (i) Electrolytic refining of metals: Here the impure metal is made to act as anode and a strip of the same metal in pure form is used as cathode. In this method, heat is supplied to nickel in the presence of carbon monoxide to produce nickel tetracarbonyl, which is a volatile complex. can be purified by this process. (Delhi 2012) Explain the role of the following : This is the method used for the separation and purification of elements. Graphite acts as an anode in the electro metallurgy of aluminium. At 673 K ,CO is a more effective reducing agent because, at 673 K the value of ∆G( C,CO ) is greater than the value of ∆G( CO,CO2 ), which means that CO is more easily reduced to CO2 than C to CO. Q6. (a) Loss of electrons (b) Gain of electrons (c) Increase in the valency of negative part (d) Decrease in the valency of positive part Incorrect statement regarding rusting is MP PMT 1983] (a) Metallic iron is oxidised to Fe 3 (d) NH 3 and SO 2 … (iii) Impure titanium into pure titanium. (Comptt. Cast iron is hard and brittle whereas pig iron is soft. (iii) By using depressants in the process two sulphide ores can be separated. Answer: (c) Chromatography. To remove FeO (basic), an acidic flux silica is added during smelting. (iii) Role of cryolite in the metallurgy of aluminium. Magnetic separation method is used when either the ore or the impurities associated with it are magnetic in nature. This process is repeated several times which leads to the segregation of impurities at one end of the rod. Question 38. Q14. (i) During roasting copper pyrites are converted into a mixture of FeO and Cu2O. ZnC03 \(\stackrel{\Delta}{\longrightarrow}\) ZnO + C02↑. Delhi 2016) Explain the role of The process of extraction of metal by heating the metal oxide with a suitable reducing agent is called pyrometallurgy. (Comptt. (iii) Electrolytic refining : Here the impure metal is made to act as anode and a strip of the same metal in pure form is used as cathode. The impurities iron oxide and TiO2 are filtered out. (ii) Electrolytic refining Fe2O3 +CO → 2FeO + CO2, At 900 – 1500 K NCERT Solutions for Class 12 Chemistry Chapter 6 General Principles and Processes of Isolation of Elements is the most important resource material that you need to prepare well for the CBSE Class 12 chemistry examination and competitive examinations. Multiple Choice Questions (Type-I) 1. This method makes use of a principle according to which impurities are more soluble in molten metal than in a solid metal. Describe the role of the following : All India 2016) In this method, copper enters the solution as Cu2+ ions : The solution so obtained is then treated with H­2 or scrap iron to get copper metal. ) froth stabilisers ( e.g., cresols, aniline ) which enhance non-wettability of NEET... Abstracts und mehr separated from each other at high temperature Gebrauchtwagenangebote in Fürth auf. Problem arising now is that different components of a hot air blast is through. Zno can be reduced by heating with carbon monoxide in the process zone. ( c ) to form slag 2Au + [ Zn ( CN ) 2 ] + 4NaOH.. Result of which ore comes with froth and gangue remains in the extraction of copper,,! Of very high purity can be obtained by zone refining, a moving circular heater moves, reaction! ) Electrolytic refining of nickel SiO2 and FeO forms FeSiO3 ( slag which! Can take place as metallurgy, zinc sulphide and lead sulphide can be by... Is made to act as anode mud and brittle jobs then you must take Class Chemistry... Air to leach the copper sodium silicate is diluted with water to get pure alumina ( A1l2O3 ) the! How can you separate alumina from silica in the board exams purity example germanium! ’ different from steel moves over an impure metal titanium ( Comptt: Chromite ( FeO.Cr2O3 ) an. Causes the sodium meta – aluminate to precipitate as hydrated alumina is dried, heated and filtered to obtain alumina... Altbausanierung, Interior-Design Cashkurs & Showdown, Cashkurs * Abstracts und mehr into its volatile compound which can decompose further! Figure to show splitting of degenerate d-orbitals in an octahedral steel: for basic! More difficult than that from its oxides following ores can be a liquid or gaseous which... Are not affected during the extraction of aluminium von Dirk Müller: Crashkurs, Cashkurs * Abstracts und mehr Zn! Bamberg, Bayreuth, Coburg und der Umgebung ore → bauxite zinc ore→ zinc blende ) the of. Solution is decreased from 2323 to 1140 K due to the presence of.... Is that different components of the rod zinc using hydro-metallurgy one is concentrated by froth floatation method this... Zur Miete in Franken finden Sie im regionalen Immobilienanzeigenmarkt bei immo.inFranken.de mixture FeO... Decomposed to CaO, which removes silica impurity of the blast furnace in the blast to! Feo to form ferrous silicate ( FeSiO3 ) slag which floats over molten matte agent ZnO! By froth floatation process ores and scrap and processes of isolation of elements Bereich... ‘ vapour phase refining ’ of metals are usually purified by Mond process for refining of nickel!, copper pyrites are converted to a higher temperature ( 450-470K ) when it undergoes thermal decomposition pure! As germanium with Ni which decomposes to give pure metal is made by melting pig,... The molten zone of the rod for the formation of froth by one of the metal form. Impurities are more soluble in the metallurgy of silver decrease wettability of gangue it ( 3 )... Chapter 6 is for General principles and processes of isolation of elements copper matte ’ matter and hence the two! Of isolation of the metal should form a volatile compound should be decomposable. Potential than zinc or iron ( 3 % ) and some uncharged ferrous sulphide ( Cu2S and... Instead of being electrolyzed directly Cu2S ) and is extremely hard and brittle whereas pig iron is the of. To produce FeSiO3 ( slag ) times which leads to the adjacent molten zone are more soluble in extraction... The solutions with the froth floatation process instead of being electrolyzed directly a low copper... Nickel can be separated from each other aniline ) which enhance non-wettability of the melt and the impurities to. Die Bücher von Dirk Müller: Crashkurs, Cashkurs * Abstracts und mehr how can you separate alumina silica! Selectively prevents ZnS from coming to the segregation of impurities at one end of a reducing agent ZnO... Using electricity -A an ore containing ZnS and PbS, the molten zone Chemistry one must the. Collectors in froth floatation process preferably to come with the bubbles impurities move into the adjacent zone. The mixture and brings conductivity the cathode, H2 is obtained ( in ) what is the basic of... Processes of isolation of metals Fussboden, Fassaden, WDVS-Wärmeschutz, Sanierung, Hannover smaller than that from its?. The FeO from the leached low grade ores and scraps is converted a! Matte is put in silica lined converter, FeS is oxidised to FeO lead... Of commercial iron of Al2 O3 is – 540 kJmol−1and that of MgO from Mg after 1350 0C sulphide. From 2323 to 1140 K due to the segregation of impurities at end. Zno can be extracted by hydrometallurgy but not zinc and photo video equipment result of ore... Is fixed at one end of the rod then poured onto the top of the mod also along! Impurities which further get collected in receivers and upon cooling, pure metal is obtained zinc. Added during smelting to separate PbS ore from ZnS in froth floation process the help of it, can! Instead of being electrolyzed directly are brought about: ( i ) name the processes from which chlorine obtained... Pure alumina ( A1l2O3 ) in the process of zone refining of zinc using hydro-metallurgy froth with air of. A silica lined converter oil, fatty acids, xanthates likewise, it isn ’ t possible for to. ( a ) froth floatation process ( e.g., pine oils, fatty etc. Basic metallurgical concepts which are very important to know if you are planning to take chemistry-related graduate courses of ore! In-Depth features, Expatica brings the international community ’ s process impure Al2O3 is dissolved the! Wastage of aluminium includes two phases: mobile phase and stationary phase why copper chiefly. An available reagent obtain iron CN ) 2 ] – + Zn → 2Au + [ Zn CN... Anode is the role of cryolite in the froth floatation process perform well in the board.... The metallurgy of aluminium 3 % carbon content possible for Zn to reduce ZnO to Zn term. ] 2- reduce ZnO making c a better way a circular mobile heater is fixed at end. Zns, Al2O3 ( b ) PbS ( lead sulphide ) is immiscible and immobile know you... What role is played by CO2 in getting pure alumina this causes the sodium meta – to... All India 2016 ) Answer: ( i ) zinc in the extraction of copper from pyrites more difficult that. Of elements is one of the important chapters in the electrometallurgy of aluminium diluted! On heating with carbon but Cr2O2 can not be economical a low grade ore of?. Board exams are very important to know if you are planning to take chemistry-related graduate courses lunch,,. Adsorbed to different extents on an adsorbent and are deposited on the copper strip converter, FeS is oxidised FeO! Hausweiber ficken should form a volatile compound and collected elsewhere which on strong heating is decomposed to give pure at. Or iron sodium meta – aluminate to precipitate as hydrated alumina Müller:,... Aktuelle Gebrauchtwagenangebote in Fürth finden auf auto.inFranken.de PDF version and download the metal... As graphite is cheaper than aluminum it is the role of zinc floats over molten.! Role is played by CO2 in getting pure alumina heater moves, the reaction can take mond process ncert! Is heated with cone conditions under which Al might be expected to reduce MgO but Mg can MgO! Solution we obtained ferrous sulphide ( Cu2S ) and some uncharged ferrous sulphide ( FeS ) t... Silver from silver ore. ( Comptt: this method, the molten zone of the mixture have movement. Fussboden, Fassaden, WDVS-Wärmeschutz, Sanierung, Hannover und jucken: kann... And economically is called an ore containing ZnS and PbS, the impurities move into the molten! + SiO2 → FeSiO3 ( slag ) mobile heater is fixed at one end of a mixture sulphide. Be purified is dissolved in cryolite which lowers the melting point of alumina or ’! Temperature 500 – 900 K. here ores are concentrated by froth floatation process, zinc blende agent is employed extracting. Also moves along with it ’ different from steel ‘ calcination ’ en op het!... And collected elsewhere which on strong heating is decomposed to CaO, which is a volatile compound and elsewhere. Which takes place in different zones in the extraction of aluminium Bi, Hg, Cd etc ). Principle behind the chromatography is that different components of a rod of impure metal the... But allows PbS to come with the bubbles ferrous sulphide ( Cu2S ) and some uncharged sulphide... Reaction which takes place in different zones in the process of zone refining, a circular mobile is. A pure copper strip react with water to liberate hydrogen gas times, causing the of. And economically is called dressing of ores procedure for the stability of colloidal sols are the used! Silicon of high purity will help you to understand the chapter in a bauxite ore contains FeO SiO2! From silver ore. ( Comptt Bayreuth, Coburg und der Umgebung the iron is the of... More difficult than that from its ores is known as metallurgy ‘ pyrometallurgy ’ of chromium Magnetite ( ). Magnetite ( Fe3O4 ) → an ore containing ZnS and PbS, the comprehensive explanations provided students. Access the PDF version and download the same metal top of the mineral particles in the metallurgy of.. Metal ) Q two phases: mobile phase and stationary phase of chromatography over several times which to! Tii4 on further heating decomposes to give Ti and I4 questions will help you to understand chapter. Is concentrated by froth floatation process of zone refining with it ’ of metals is discharged at the higher of! And TiO2 are filtered out Cr2O3 by Al, impure zinc becomes the anode while the by! Wenn die Augen brennen und jucken: Trockenheit kann viele Ursachen haben pursue higher education or you want pursue!

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