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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.
| 101. |
In the stages involved in the extraction of metals in general – give reasons for the following. Conversion of concentrated ore to its oxide is an essential step in the extraction of metals from the ore, even then the step is not necessary in the metallurgy of aluminium. |
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Answer» Conversion of concentrated ore to its oxide is an essential step in the extraction of metals from the ore, even then the step is not necessary in the metallurgy of aluminium because in metallurgy of aluminium, the ore is already an oxide. |
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| 102. |
`X+CuSO_(4)toXSO_(4)+Cu`, `Y+CuSO_(4)toYSO_(4)+Cu`, in these reactions X and Y may be ______ .A. Zn, AgB. Zn, FeC. Fe, AgD. Ag, Al |
| Answer» Zn and Fe are more reactive than copper. | |
| 103. |
Give the (i) common (ii) chemical nadie (iii) formula of two common ores each of aluminium, zinc and iron. |
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| 104. |
In the stages involved in the extraction of metals in general – give reasons for the following. Dressing of the ore is an essential process in the extraction of metal from its ore. |
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Answer» The ores are found mixed with earthy impurities like sand, clay, lime stone etc. These unwanted impurities in the ore are called gangue or matrix. The process of removal of gangue from powdered ore is called concentration or ore dressing. Hence, it is the essential process in the extraction of metal from its ore because it convert’s the impure ore to pure concentrated ore |
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| 105. |
The device used for grinding on ore. |
| Answer» Correct Answer - Ball mill | |
| 106. |
Thermite is a mixture of `:`A. Fe powder and `Al_(2)O_(3)`B. Al powder and `Fe_(2)O_(3)`C. Cu powder and `Fe_(2)O_(3)`D. Zn powder and `Cr_(2)O_(3)` |
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Answer» Correct Answer - B Al powder and `Fe_(2)O_(3)` |
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| 107. |
What are the modertaly reative metals ? |
| Answer» The metals ppresent in the middle of reactivity series are called as, moderately reactivty metals e.g. Zinc, Iron, Lead, Tin, Copper. | |
| 108. |
The compositio of thermite mixture isA. iron (III) oxide and aluminium powder in the rato 1 : 3B. aluminium powder and iron (III) oxide in the ratio 1 : 3C. aluminium powder and barium peroxide in the ratio 1 : 3D. barium peroxide and aluminium in the ratio 1 : 3 |
| Answer» Thermite mixture is 1 : 3 ratio of Al powder and ferric oxide. | |
| 109. |
The order of procsses involved in the dressing of an ore is (i) grinding and crushing (ii) hand-picking (iii) PulverisationA. (i), (ii), (iii)B. (i), (iii), (ii)C. (ii), (iii), (i)D. (ii), (i), (iii) |
| Answer» Dressing of ore can be carried out by hand-picking, crushing and grinding, Pulverisation. | |
| 110. |
In which form do the moderately reactive metals occur in nature |
| Answer» The metals are usually present as Sulphides or Carbonates in nature. | |
| 111. |
In which form to the moderately reactive metals occur in nature? |
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Answer» The moderately reactive metals which occur in nature are in the form of their sulphide salts or carbonate salts. |
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| 112. |
Which method, is used for the uprfication of more reactive metals ?A. Chemical reductionB. RoastingC. CalciunationD. Electrolytic reduction |
| Answer» Electrolytic redction | |
| 113. |
The main consituent of bauxite is ___________A. `Al_(2)O_(3)`B. `Al_(2)(SO_(4))_(3)`C. `CaSO_(4)`D. `Na_(3)AlF_(6)` |
| Answer» `Al_(2)O_(3)` | |
| 114. |
The most lustrous substance. |
| Answer» Correct Answer - Diamond | |
| 115. |
The process of converting sulphite ores into oxides by heating strongly in excess of air is called calcination. |
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Answer» Correct Answer - Fasle. The process of voerting sulphide ores into oxides by heating strongl in air is called roasting |
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| 116. |
Cinnabar is an ore of ___________A. AluminiumB. SodiumC. IronD. Mercury |
| Answer» Correct Answer - Mercury | |
| 117. |
Alloy of sodium with mercury. |
| Answer» Sodium amalgam. | |
| 118. |
Native silver metel froms a water solube, complesx with a dilute aqueous wsolution of `NaCN` in the presence ofA. nitrogenB. oxygenC. carbon dioxideD. argon |
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Answer» Correct Answer - B Reaction is reversible so to get the maximum yield of the product , the reaction is carried out in presence of oxygen. Also oxygen oxidises silver `(I)` ion which then produces soluble complex with CN ions. `2Ag+4 NaCN+1/2 O_(2)+H_(2)O hArr 2Na[Ag(CN)_(2)]+2NaOH`. |
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| 119. |
Which metal alloy is used in design of aeroplane parts? (a) Al (b) Zn (c) Cu (d) Au |
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Answer» Al is used in design of aeroplane parts. |
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| 120. |
Select correct statementA. In the decomposition of an oxide into oxygen and solid`//` liquid metal, entropy increases.B. Decomposition of an oxide is an endothermic change.C. To make `DeltaG^(@)` negative, temperature should be high enough so that `T DeltaS^(@) gt DeltaH^(@)`.D. All are correct statements. |
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Answer» Correct Answer - 4 `(1)` When the oxide undergoes a phase change, there will be an increase in the entropy of the oxide. `(2)` It is true statements, `HgOoverset(Delta)rarrHg+1//2O_(2)` `(3)` For a reduction process the change in the free energy `, DeltaG^(@)` must be negative and to make `DeltaG^(@)` negative temperature should be high enough so that `T Delta S^(@) gtDeltaH^(@)`. |
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| 121. |
An ore of Mercury. |
| Answer» Cinnbar (HgS) | |
| 122. |
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) – Aluminium is used in the j design of chemical reactors.Reason (R) – Aluminium has high resistance to corrosion. |
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Answer» (a) A and R are correct, R explains A |
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| 123. |
Which does not represent correct method ?A. `TiCl_(2)+2Mgrarr Ti+2MgCl_(2)" ":` KrollB. `Ni(CO)_(4)rarr Ni+4CO" ":`MondC. `Ag_(2)CO_(3)rarr2Ag+CO_(2)+(1)/(2)O_(2)" ":` Van ArkelD. `ZrI_(4)rarrZr+2I_(2)" ":`Van Arkel |
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Answer» Correct Answer - 3 This process is simply calcination. |
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| 124. |
i. Alloy of sodium with mercury.ii. Molecular formula of common ore of aluminium.iii. The oxide that forms salt and water by reacting with both acid and base.iv. device used for grinding an ore.v. The nonmetal having electrical conductivity.vi. The reagent that dissolves noble metals. |
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Answer» i. Silver amalgam. ii. Al2O3.nH2O iii. Aluminium oxide (Al2O3). iv. The device used for grinding an ore is grinding mill. v. Graphite having electrical conductivity. vi. Aqua regia is the reagent that dissolves noble metals like gold and platinum. |
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| 125. |
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) – Zone refining is based on the principles of fractional crystallisation,Reason (R) – This process is carried out in an inert gas temperature. |
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Answer» (b) A and R are correct, R does not explain A |
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| 126. |
The process of zone refining is used for `:`A. siliconB. germaniumC. galliumD. all the above |
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Answer» Correct Answer - 4 This process is used when metals are required in very high purity, for specific application. For example pure Si and Ge are used in semiconductors and hence are purified by this method. Zone refining method is based on the principle that an impure molten metal on gradual cookling will deposit crystals of the pure metal, while the impurities will be left in the remaining part of the molten metal. |
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| 127. |
An alkaline earth metal(A) Potassium (B) Calcium (C) Lead (D) Copper |
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Answer» An alkaline earth metal is Calcium. |
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| 128. |
Explain zone refining process with an example using the Ellingham diagram given below. |
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Answer» 1. Zone Refining method is based on the principles of fractional crystallisation. When an impure metal is melted and allowed to solidify, the impurities will prefer to be in the molten region, i.e. impurities are more soluble in the melt than in the solid state metal. 2. In this process, the impure metal is taken in the form of a rod. One end of the rod is heated using a mobile induction heater which results in melting of the metal on that portion of the rod. 3. When the heater is slowly moved to the other end the pure metal crystallises while the impurities will move on to the adjacent molten zone formed due to the movement of the heater. As the heater moves further away, the molten zone containing impurities also moves along with it. 4. The process is repeated several times by moving the heater in the same direction again and again to achieve the desired purity level. 5. This process is carried out in an inert gas atmosphere to prevent the oxidation of metals. 6. Elements such as germanium (Ge), silicon (Si) and galium (Ga) that are used as semiconductor are refined using this process. |
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| 129. |
Name the main ore of aluminium. |
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Answer» Bauxite (Al2O3.H2O) is the main ore of aluminium. |
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| 130. |
Write the constituents of electrolyte for – the extraction of aluminium. |
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Answer» 1. Fused Alumina (Al2O3) 1 part by weight. 2. Cryolite fused (Na3 AlF6) 3 part by weight. 3. Fluorspar (CaF2) 1 part by weight. |
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| 131. |
Zone refining is based on the principle thatA. impurities of low boiling metals can be separated by distillationB. impurities are more soluble in molten metal than in solid metalC. different components of a mixture are differently absorbed on an adsorbentD. vapours of volatile compound can be decomposed into pure metal |
| Answer» (b) `CaSiO_(3)` is called slag which is fusible and lighter than the molten metal and is removed easily. | |
| 132. |
The process in which the concentrated ore is strongly heated in the absence of air is called as …………… (a) Roasting (b) Calcination (c) Smelting (d) Leaching |
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Answer» (b) Calcination |
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| 133. |
Non- metal bromien exists in ________ |
| Answer» liquid state | |
| 134. |
Write the chemical formulae of one main ore – of iron and aluminium. |
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Answer» Iron : Haematite → Fe2O3 Aluminium : Bauxite → Al2 ,O3 .2H2O. |
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| 135. |
Name on ore which is concentrated by this method and also write thw tow ingredients with molecular formulae, present in this ore. |
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Answer» The ore which concentrated by this method is cassiterite. Cassiteriteis a ore. It contains mainly the nonmagnetic ingredient stannic oxide `(SnO_(2))` and the magnetic ingredient ferrous tungstate `(FeWo_(4))` |
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| 136. |
A chemist involves mining process and he got tow ores mixed together. If one is tinstone and another one is chromite, which type of process will be used to separate that two ores? (a) Leaching process (b) Froth floatation process(c) Zone refining process (d) Magnetic separation process |
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Answer» (d) Magnetic separation process |
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| 137. |
Describe the seperaton metod which are based on gravitation. |
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Answer» Seperation method based on gravitation- The heavy particels of ores can be easily separated from the ligh particles of gangue by the gravitationla method. The process to carry out this separation are as follows : (ii) Wilfley table method : (a) In this method of seperation, the Wilfley table is made by fixin narrow and thin wooden riffles on inclined surface. (b) The table is kept vibrating continuously. (c) Powedered ore obtained from lupms of hte ore using ball mill is poured on the table and stream of water is also released from the upper side. (d) As a result, the lighter gangue particles are carried away along with the flowing water, while the is more aand wooden riffles and get collected on the slits between them. (ii) Hydraulic separation method : (a) The hydraulic separation method is based on the working of a mill. (b) There is a tapering vessle similar to that used in a grinding mill. (c) It opens is a tank-like container that is tapering on the lower side. (d) The tannk has an outlet water on the upper side and a water inlet on the lower side. (e) Finely grounded ore is reasled in the tank. (f) A forceful jet of water is introduced in teh tank from the lower side. (g) Gangue particles are lighter and therefore they flow out along with the water jet from teh outlet on the upper side of the tank get collected seaprately. (h) At the time the heavy particles of the ore are collected at the bottom from the lower side of the tank. In short, this method is based on the law of gravitation, where in particles of the same size are separated by their weight with the help of water. |
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| 138. |
Give the chemical formulae of the following naturally occuring ores:1. Cryolite2. Galena3. Corund um4. Dolomite5. Zincite6. Malachite7. Cinnabar8. Gypsum9. Horn silver10. Epsom salt11. Haematite12. Bauxite |
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Answer» 1. Na3AlF6 2. PbS 3. AI2O3 4. CaCO3.MgCO3 5. ZnO 6. CuC O3.Cu(OH)2 7. HgS 8. CaSO4.2H2O 9. AgCl 10. MgS O4. 7H2O 11. Fe2O3 12. Al 2O3.2H2O |
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| 139. |
Match the metals/alloys – brass, with its correct use. Uses : (a) steel making (b) aeroplane wings (c) galvanizing (d) radiation shield (e) electrical fittings |
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| 140. |
The alkali metals from group 1 such as Lithium, Sodium, and Potassium are very __________ |
| Answer» Correct Answer - Soft | |
| 141. |
Answer the questions based on the given diagram. Label the diagram and answer the given question What is the importance of cryoite and fluorspar ? |
| Answer» Cryolite `(NaAlF_(6))` and fluorspar `(CaF_(2))` are added in the mixture to lower its metling point upto `1000^(@)C`. | |
| 142. |
A metal which does not react with cold water but reacts with steam. |
| Answer» Correct Answer - Iron | |
| 143. |
An alloy of copper and zinc |
| Answer» Correct Answer - Brass | |
| 144. |
In the reaction between chlorine and HBr a transformation of HBr into, `Br_(2)` takes place. Can this transformation be called oxidation ? Which is the oxidant that brings about this oxidation. |
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Answer» When chlorine react with hydrobromic acid, bromine is formed. `Cl_(2(g))+2HBr_((aq)) to 2HCl_((aq))+ Br_(2)`. Yes, this transformation is called oxidation, as hydrobromide acid loses hydrogen. In this reaction `Cl_(2)` is the oxidizing agent. |
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| 145. |
Which gas is generally liberated when metals react with dilute acid? |
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Answer» Hydrogen gas is generally liberated when metals react with dilute acid. |
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| 146. |
What is the purpose of roasting in metallurgy ? |
| Answer» In metallurgy, the purpose of roasting is the converstion of Sulphide ore into oxide by strongly heating it in air. | |
| 147. |
Find the odd one out and give the reasons:(a) Silver(b) Gold(c) Sodium (d) Platinum |
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Answer» (c) Sodium Reason: Sodium is more reactive element than Ag, Au and Pt. |
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| 148. |
What acts as cathod ein electrolytic reduction of `Al_(2)O_(3)?` |
| Answer» Carbon (graphite) lining inside the Steel tank acts as a cathode in electrolytic reduction of `Al_(2)O_(3)` | |
| 149. |
Mention the uses of Gold (Au). |
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Answer» The uses of Gold (Au) are : 1. Gold, one of the expensive and precious metals. It is used for coinage, and has been used as standard for monetary systems in some countries. 2. It is used extensively in jewellery in its alloy form with copper. It is also used in electroplating to cover other metals with a thin layer of gold which are used in watches, artificial limb joints, cheap jewellery, dental fillings and electrical connectors. 3. Gold nanoparticles are also used for increasing the efficiency of solar cells and also used an catalysts. |
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| 150. |
Match the following:(i) Aluminium – (a) cosmetics (ii) Zinc oxide – (b) gas pipelines (iii) Iron – (c) making coins (iv) Copper – (d) bicycle chains |
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Answer» (i) – (b) (ii) – (a) (iii) – (d) (iv) – (c) |
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