

InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
401. |
What are the various alloys used in daily life ? |
Answer» (i) Brass and Bronnze are two alloys which we use in our daily life. (ii)Brass is an alloly of copper and zin c and Bronze is an alloy of copper and tin. (iii) Brass is used for decorative articles and for making musical instruments. (iv) Bronze is uded for making medals, sculptures, statues cooking utensile and coins. |
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402. |
Statement-I : Wolframite impurities are separated from cassiterite by electromagnetic separation Statement-II : Cassiterite being magnetic is attached by the magnet and forms a separate heap.A. Statement-I is True, Statement-II is True, Statement-II is a correct explanation for Statement-IB. Statement-I is True, Statement-II is True, Statement-II is NOT a correct explanation for Statement-IC. Statement-I is True, Statement-II is False.D. Statement-I is False, Statement-II is True. |
Answer» Correct Answer - C | |
403. |
Gravity separation methode is based upon `:`A. preferential washing of ores and gangue particles.B. difference in densities of ore particles and impurities.C. differnece in chemical properties of ore particles and impuritiesD. None of these |
Answer» Correct Answer - 2 Hydraulic washing or Gravity separation of Levigation method is based on the difference in the densities of the gangue and ore particles. |
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404. |
What are the properties that the alloy used for minting coins should have ? |
Answer» Alloys used for minting coins should be ductile and malleable. | |
405. |
Refining of Iron is done by-A. Electrolytic methodB. Zone refiningC. PolingD. Selective oxidation |
Answer» Correct Answer - C | |
406. |
Extraction of gold and silver involves leaching with cyanide ion. Silver is later recovered by ……………… (a) Distillation (b) Zone refining (c) Displacement with zinc (d) liquation |
Answer» (c) Displacement with zinc |
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407. |
Statement-I : In the smelting of copper ore coke is added in the blast furnace. Statement-II : Coke reduced, `CuO` into `Cu`.A. Statement-I is True, Statement-II is True, Statement-II is a correct explanation for Statement-IB. Statement-I is True, Statement-II is True, Statement-II is NOT a correct explanation for Statement-IC. Statement-I is True, Statement-II is False.D. Statement-I is False, Statement-II is True. |
Answer» Correct Answer - C | |
408. |
During metallurgy of iron its, ore coke and limestone are added to the blast furnace. (a) What is the role of limestone? (b) Identify the reducing agent in the extraction of iron during the above process. (c) Identifly slag formed during the above process. (d) What are the different gases liberated in this process? |
Answer» (a) Limestone `(CaCO_(3))` undergoes thermal decomposition and gives CaO and `CO_(2)`. CaO acts as a flux. (b) Carbon monoxide acts as a reducing agent: `FeO+COtoFe+CO_(2)` `Fe_(2)O_(3)+3COto+3CO_(2)` (c) CaO reacts with the impurity `SiO_(2)` and forms the slag `CaSiO_(3)`: `CaO+SiO_(2)toCaSiO_(3)` (d) `C+O_(2)toCO_(2)(g)` `CO_(2)+Cto2CO(g)` `CaCO_(3)toCaO+CO_(2)(g)` `FeO+COtoFe+CO_(2)(g)` `Fe_(2)O_(3)+3COto2Fe+3CO_(2)(g)` `CO_(2)` gas is liberated. CO gas is formed, but takes part in the process of erduction of `Fe_(2)O_3)` and forms `CO_(2)`. |
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409. |
Magnetic separation is used for increasing concentration of the followingA. Horn silverB. CalciteC. HamatiteD. Magnesite |
Answer» Correct Answer - C | |
410. |
Steel consists of.....percentage of carbon-A. `3.1 -4.5%`B. `2.2 -3.1%`C. `0.15 -0.28%`D. `0.15 -1.5%` |
Answer» Correct Answer - D | |
411. |
What is Acid leaching? |
Answer» Leaching of sulphide ores such as ZnS, PbS etc,, can be done by treating them with hot aqueous sulphuric acid. 2ZnS(s) + 2H2SO4 (aq) + O2 (g) → 2ZnSO4 (aq) + 2S (s) + H2O In this process the insoluble sulphide is converted into soluble sulphate and elemental sulphur. |
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412. |
Explain Cyanide leaching. |
Answer» In the concentration of gold ore, the crashed ore of gold is leached with aerated dilute solution of sodium cyanide. Gold is converted into a soluble cyanide complex. The gangue, aluminosilicate remains insoluble. 4Au (s) + 8CN- (aq) + O2 (g) + 2H2O (l) → 4[Au(CN)2]- (aq) + 4OH- (aq) |
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413. |
What is Ammonia leaching. |
Answer» When a crashed ore containing nickel, copper and cobalt is treated with aqueous ammonia . under suitable pressure, ammonia selectively leaches these metals by forming their soluble complexes viz. [Ni(NH3)6]2+ , [Cu(NH3)4]2+ , and [Co(NH3)5H2O]3+ respectively from the ore leaving behind the gangue, iron(III) oxides/hydroxides and aluminosilicate. |
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414. |
Haematite ore having magnetic property can be separated by magnetic separation In blast furnace, iron oxide is reduced by-A. SilicaB. `CO`C. `C`D. lime stone |
Answer» Correct Answer - B | |
415. |
The metal oxide which cannot be reduced to metal by carbon is ………… (a) PbO (b) Al2O3(C) ZnO (d) FeO |
Answer» The metal oxide which cannot be reduced to metal by carbon is Al2O3 |
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416. |
Complete the following by selecting the correct option from the choices given – 1. The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction _____ [Fe / Mg / Pb / Al] 2. The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is _____ [Al / Na / Mg / K] |
Answer» 1. The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction Pb (Lead). 2. The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is Mg (Magnesium). |
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417. |
Write a notes on alkali leaching process? |
Answer» In this method, the ore is treated with aqueous alkali to form a soluble complex. For example, bauxite, an important ore of aluminium is heated with a solution of sodium hydroxide or sodium carbonate in the temperature range 470 – 520 K at 35 atm to form soluble sodium meta- aluminate leaving behind the impurities, iron oxide and titanium oxide Al2O3 (S) + 2NaOH (aq) + 3H2O (l) → 2Na[Al(OH)4] (aq) The hot solution is decanted, cooled, and diluted. This solution is neutralised by passing CO gas, to the form hydrated Al2O3 precipitate. 2Na[Al(OH)4](aq) + CO2 (g) → Al2O3. xH2O(s) + 2NaHCO3 (aq) The precipitate is filtered off and heated around 1670 K to get pure alumina Al2O3. |
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418. |
Write notes on liquation. |
Answer» Liquation: This method, is employed to remove the impurities with high melting points from metals having relatively low melting points such a stin(Sb;mp=904K), lead(Pb;mp=600K), mercury(Hg; mp = 234 K), and bismuth (Bi; mp = 545K). In this process, the crude metal is heated to form fusible liquid and allowed to flow on a sloping surface. The impure metal is placed on sloping hearth of a reverberatory furnace and it is heated just above the melting point of the metal in the absence of air, the molten pure metal flows down and the impurities are left behind. The molten metal is collected and solidified. |
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419. |
In the commercial electrochemical process for aluminium extraction, the electrolyte used isA. `AI(OH)_(3)` in `NaOH` solutionB. An aqueous solution of `AI_(2)O_(3)` and `Na_(3)AIF_(6)`C. A molten mixture of `AI_(2)O_(3)` and `Na_(3)AIF_(6)`D. A molten mixture of `AIO(OH)` and `AI(OH)_(3)` |
Answer» Correct Answer - C | |
420. |
Cassiterite ore `(SnO_(2))` is purified byA. Magnetic separatorB. RoastingC. LeachingD. Calcination |
Answer» Correct Answer - A Tin stone contain magnetic impurity wolfaurite `FeWO_(4)` |
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421. |
Find the odd one out and give the reasons: (a) Haematite (b) Siderite (c) Limonite (d) Azunte |
Answer» (a) Azurite Reason: Azurite is ore of copper but others arc ore of iron. |
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422. |
The reaction (s) which does (do) not occur in the reduction zone in the extraction of iron from haematite ore is (are)A. `Fe_(2)O_(3) +CO rarr 2FeO +CO_(2)`B. `FeO +Co rarr Fe +CO_(2)`C. `Fe_(2)O_(3) +3C rarr 2Fe +3CO`D. `CaO + SiO_(2) rarr CaSiO_(3)` |
Answer» Correct Answer - C::D `CaO +SiO_(2) rarr CaSiO_(3) (slag) 1000^(@)C` `Fe_(2)O_(3) +3C rarr 2Fe +3CO` At.v.v high T. (Not possible in one step) |
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423. |
Haematite and tin stone are purified by ……………(a) gravity separation process (b) magnetic separation process (c) froth floatation process (d) handpicking |
Answer» (a) gravity separation process |
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424. |
Consider the following metallurgical processes`:` `(I)` Heating impure metal with `CO` and distilling the resulting volatile carbonyl `(b.p. 43^(@)C)` and finally decomposition at `150^(@)-200^(@)C` to get the pure metal. `(II)` Heating the sulphide ore in air until a part is converted to oxide and then further heating in the absence of air to let the oxide react with unchanged metal sulphide. `(III)` Electrolysis of the molten electrolyte containing approximately equal amounts of the metal chloride and NaCl to obtain the metal. The processes used for obtaining magnesium , nickel and copper are respectively.A. `(I),(II)` and `(III)`B. `(II),(III)` and `(I)`C. `(III),(I)` and `(II)`D. `(II) ,(I)` and `(III)` |
Answer» Correct Answer - 3 | |
425. |
In the metallurgical process for the electro-refining of the metal, the anode is made of ...........metal. |
Answer» Correct Answer - Inpure | |
426. |
Oxide ores are concentrated by …………… (a) handpicking (b) hydraulic washing (c) froth floatation process (d) Magnetic separation process |
Answer» (b) hydraulic washing |
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427. |
Describe the method of refining of Zirconium and Titanium. |
Answer» Van Arkel process is used for obtaining ultrapure metal. The impure metal is converted into volatile compound, which then decomposes electrically to get pure metal. At 850K: - Zr (impure) + 2 I2 → ZrI4 At 2075K:- ZrI4 → Zr (pure) + 2 I2 |
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428. |
What are all the steps involved in metallurgical process? |
Answer» The extraction of a metal from its ore consists the following metallurgical process. 1. Concentration of the ore 2. Extraction of crude metal 3. Refining of crude metal |
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429. |
Flux is a substance which is used to convert ……………(a) Mineral into silicate (b) Infusible impurities to soluble impurities (c) Soluble impurities to infusible impurities (d) All of these |
Answer» (b) Infusible impurities to soluble impurities |
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430. |
Titanium is purified by …………… (a) Mond process (b) Van-Arkel method (c) Zone refining (d) Electrolytic refining |
Answer» (b) Van-Arkel method |
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431. |
Name the method used for the refining of 1. Nickel 2. Zirconium |
Answer» 1. Mond’s process 2. Van Arkel’s method |
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432. |
The oxides will decompose on heating even in the absence of a reducing agent is …………… (a) Ag O (b) HgO (c) MgO (d) both (a) and (b) |
Answer» (d) both (a) and (b) |
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433. |
The selection of reducing agent depends on the thermodynamic factor. Explain with an example. |
Answer» From the Ellingham diagram, it is clear that metals for which the standard free energy of formation (∆fG0) of their oxides is more negative can reduce the metal oxides for which the standard free energy of formation (∆fG0) of oxides is less negative. Thermodynamic factor has a major role in selecting the reducing agent for a particular reaction. Only that reagent will be preferred which will lead to decrease in the free energy (AG°) at a certain specific temperature. E.g – Carbon reduce ZnO to Zn but not CO.
In the first case, there is increase in the magnitude of ∆S° while in the second case, it almost remains the same. In other words, ∆G° will have more negative value in the first case, when C is the reducing agent then in the second case when CO acts as the reducing agent. Therefore, C is a better reducing agent. |
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434. |
Ag2(g)O and HgO are unstable at moderate temperature and they will decompose on heating even in the absence of a reducing agent. Why? |
Answer» Ellingham diagram for the formation of Ag2(g)O and HgO is at upper part of the diagram and their decomposition temperatures are 600 and 700 K respectively. It indicates that these oxides are unstable at moderate temperatures and will decompose on heating even in the absence of a reducing agent. |
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435. |
The impurities associated with ores is …………… (a) flux (b) slag (c) gangue (d) metal |
Answer» The impurities associated with ores is gangue |
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436. |
Mention the applications of Aluminium. |
Answer» Aluminium is the most abundant metal and is a good conductor of electricity and heat. It also resists corrosion. The following are some of its applications. 1. Many heat exchangers/sinks and our day to day cooking vessels are made of aluminium. 2. It is used as wraps (aluminium foils) and is used in packing materials for food items, 3. Aluminium is not very strong, However, its alloys with copper, manganese, magnesium and silicon are light weight and strong and they are used in design of aeroplanes and other forms of transport. 4. As Aluminium shows high resistance to corrosion, it is used in the design of chemical reactors, medical equipments,refrigeration units and gas pipelines. 5. Aluminium is a good electrical conductor and cheap, hence used in electrical overhead electric cables with steel core for strength. |
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437. |
Discuss the applications of the Ellingham diagram: |
Answer» Ellingham diagram helps us to select a suitable reducing agent and appropriate temperature range for reduction. The reduction of a metal oxide to its metal can be considered as a competition between the element used for reduction and the metal to combine with oxygen. If the metal oxide is more stable, then oxygen remains with the metal and if the oxide of element used for reduction is more stable, then the oxygen from the metal oxide combines with elements used for the reduction. From the Ellingham diagram, we can infer the relative stability of different metal oxides at a given temperature. 1. Ellingham diagram for the formation of Ag2O and HgO is at upper part of the diagram and their decomposition temperatures are 600 and 700 K respectively. It indicates that these oxides are unstable at moderate temperatures and will decompose on heating even in the absence of a reducing agent. 2. Ellingham diagram is used to predict thermodynamic feasibility of reduction of oxides of one metal by another metal. Any metal can reduce the oxides of other metals that are located above it in the diagram. For example, in the Ellingham diagram, for the formation of chromium oxide lies above that of the aluminium, meaning that Al2O3 is more stable than Cr2O3 . Hence aluminium can be used as a reducing agent for the reduction of chromic oxide. However, it cannot be used to reduce the oxides of magnesium and calcium which occupy lower position than aluminium oxide. 3. The carbon line cuts across the lines of many metal oxides and hence it can reduce all those metal oxides at sufficiently high temperature. Let us analyse the thermodynamically favourable conditions for the reduction of iron oxide by carbon. Ellingham diagram. for the formation of FeO and CO intersects around 1000 K. Below this temperature the carbon line lies above the iron line which indicates that FeO is more stable than CO and hence at this temperature range, the reduction is not thermodynamically feasible. However, above 1000 K carbon line lies below the iron line and hence, we can use coke as reducing agent above this temperature. The following free energy calculation also confirm that the reduction is thermodynamically favoured. From the Ellingham Diagram at 1500 K:
Reverse the reaction (1)
Now couple the reactions (2) and (3)
The standard free energy change for the reduction of one mole of FeO is: ∆G3/2 = -65 kJ mol-1. |
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438. |
Explain the method to purify Titanium metal. [OR] Explain Van-Arkel method for refining Titanium. [OR] How will you purify metals by using iodine? |
Answer» This method is based on the thermal decomposition of metal compounds which lead to the formation of pure metals. Titanium and zirconium can be purified using this method. For example, the impure titanium metal is heated in an evacuated vessel with iodine at a temperature of 550 K to form the volatile titanium tetra-iodide.(TiI4). The impurities are left behind, as they do not react with iodine. Ti(s) + 2I2(s) → TiI4 (vapour) The volatile titanium tetraiodide vapour is passed over a tungsten filament at a temperature around 1800 K. The titanium tetraiodide is decomposed and pure titanium is deposited on the filament. The iodine is reused. Til4 (vapour) → Ti(s) + 2I2(s) |
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439. |
In a metallurgical process, an acid flux is used for removing …………… (a) Slag (b) basic flux (c) acidic gangue (d) basic gangue |
Answer» (d) basic gangue |
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440. |
In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.(a) A and R are correct, R explains A (b) A and R are correct, R does not explains A (c) A is correct but R is wrong (d) A is wrong but R is correctAssertion(A) – A suitable reducing agent is selected based on the thermodynamic consideration.Reason (R) – The reduction of metal oxide with a given reducing agent can occur if the free energy change for the coupled reaction is positive. |
Answer» (c) A is correct but R is wrong |
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441. |
Explain Auto reduction. |
Answer» Simple roasting of some of the ores give the crude metal. In such cases, the use of reducing agents is not necessary. For example, mercury is obtained by roasting of its ore cinnabar (HgS) HgS (s) + O2(g) → Hg (l) + SO2 ↑ |
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442. |
The process of the removal of impurities from a crude metal is called …………… (a) concentration (b) calcination (c) refining (d) roasting |
Answer» (c) refining |
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443. |
In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.(a) A and R are correct, R explains A (b) A and R are correct, R does not explains A (c) A is correct but R is wrong (d) A is wrong but R is correctAssertion(A) – Sulphide ores are concentrated by froth floatation process. Reason (R) – Sulphide ores are preferentially wetted by oil can be separated from gangue. |
Answer» (a) A and R are correct, R explains A |
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444. |
Give the depressing agents used in the froth floatation process and why we use depressing agents in that process? |
Answer» Generally sodium cyanide and sodium carbonate are used as an depressing agents for froth floatation process. These reagents are used to selectively prevent other metal sulphides from coming to the froth. For example, when impurities such as ZnS is present in galena (PbS), sodium cyanide (NaCN) is added to depresses the flotation property of ZnS by forming a layer of zinc complex Na2[Zn(CN)4] on the surface of zinc sulphide. |
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445. |
Heating mixture of Cu2O and Cu2S will give …………… (a) Cu + SO2 (b) Cu + SO3(c) CuO + CuS (d) Cu2SO3 |
Answer» (a) Cu + SO2 |
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446. |
Which of the following metal is obtained by self reduction method? (a) Fe (b) Cu (c) Ag (d) Mg |
Answer» Cu is obtained by self reduction method. |
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447. |
Which one of the following ore is best concentrated by froth floatation method? (a) Magnetite (b) Malachite (c) Galena (d) Haematite |
Answer» Galena is best concentrated by froth floatation method. |
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448. |
In the stages involved in the extraction of metals in general – give reasons for the following. In the froth floatation process, the ore floats on the top & the gangue settles down. |
Answer» The impurities get wetted by water and remain behind in the tank. Since, the ore is lighter, it comes on the surface with the froth and the impurities(gatlgue) are left behind. |
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449. |
In the froth floatation process for the facilitation of ores the ore particles float becauseA. their surface do not get easily wetted by waterB. they are lightC. they bear electrostatic chargeD. they are not soluble |
Answer» (a) In the froth floatation process for the facilitation of ores the ore particles float because their surface do not get wetted by water. | |
450. |
Extraction of iron from zine blende is achieved byA. electrolytic reductionB. roasting followed by reduction with carbonC. roasting followed by reduction with another metalD. roasting followed by self-reduction |
Answer» Correct Answer - B | |