Metallurgy PYQs Set 5 (PDF)

Set 5 of 8 · Questions 121-150 of 225

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Metallurgy · Set 5 (Q121-150)
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121. $The plot shows the variation of -ln Kp versus temperature for the two reactions. M(s) + \frac{1}{2} O_{2} (g) \to MO(s) and C(s) + \frac{1}{2} O_{2} (g) \to CO(s) Identify the correct statement:$ (1) $At T > 1200 K, carbon will reduce MO(s) to M(s).$ (2) $At T < 1200 K, oxidation of carbon is unfavourable.$ (3) $Oxidation of carbon is favourable at all temperatures.$ (4) $At T < 1200 K, the reaction MO(s) + C(s) \to M(s) + CO(g) is spontaneous$ 122. $The reducing agent in the given equations:$ (1) $Zn$ (2) $O_{2}$ (3) $H_{2} O$ (4) $CN^{-}$ 123. $Match List I with List II : (Both having metallurgical terms) Choose the correct answer from the options given below :$ (1) $(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)$ (2) $(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)$ (3) $(a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)$ (4) $(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)$ 124. $Carbon cannot reduce Fe_{2} O_{3} to Fe at a temperature below 983 K because$ (1) $free energy change for the formation of CO is more negative than that of Fe_{2} O_{3}$ (2) $CO is themodynamically more stable than Fe_{2} O_{3}$ (3) $carbon has higher affinity towards oxygen than iron$ (4) $iron has higher affinity towards oxygen than carbon.$ 125. $Δ G^{\circ} vs T plot in the Ellingham's diagram slopes downwards for the reactions$ (1) $Mg + O_{2} \to MgO$ (2) $2 Ag + O_{2} \to Ag_{2} O$ (3) $C + O_{2} \to CO$ (4) $none of the above$ 126. $Aluminium is extracted from alumina (Al_{2} O_{3}) by electrolysis of a molten mixture of$ (1) $A l_{2} O_{3} + H F + N a A l F_{4}$ (2) $A l_{2} O_{3} + C a F_{2} + N a A l F_{4}$ (3) $A l_{2} O_{3} + N a_{3} A l F_{6} + C a F_{2}$ (4) $A l_{2} O_{3} + K F + N a_{3} A l F_{6} (2012)$ 127. $Which process use in smelting during metallurgy of coper$ (1) $Self reduction of copper$ (2) $C u_{2} S is converted into C u_{2} O$ (3) $FeS convert into FeO$ (4) $Reduction of Fe$ 128. $Which one of the following reactions does not occur during extraction of copper ?$ (1) $2 C u_{2} S + 3 O_{2} \to 2 C u_{2} O + 2 S O_{2}$ (2) $2FeS + 3 O_{2} \to 2FeO + 2 S O_{2}$ (3) $CaO + S i O_{2} \to C a S i O_{3}$ (4) $FeO + S i O_{2} \to F e S i O_{3}$ 129. $Which of the following reaction is an example of calcination process ?$ (1) $2Ag + 2HCl + [O] 2AgCl + H2O$ (2) $2Zn + O2 2ZnO$ (3) $2ZnS + 3O2 2ZnO + 2SO2$ (4) $MgCO3 MgO + CO2$ 130. $The correct statement regarding the given Ellingham diagram is: [JEE(Main)2019 Online (09-01-19), 4/120]$ (1) $At 1400ºC, Al can be used for the extraction of Zn from ZnO$ (2) $Coke cannot be used for the extraction of Cu from C u_{2} O$ (3) $At 800ºC, Cu can be used for the extraction of Zn from ZnO$ (4) $At 500ºC, coke can be used for the extraction of Zn from ZnO$ 131. $The point of intersection and sudden increase in the slope, in the diagram given below, respectively, indicates:$ (1) $Δ G = 0 and melting or boiling point of the metal oxide$ (2) $Δ G > 0 and decomposition of the metal oxide$ (3) $Δ G < 0 and decomposition of the metal oxide$ (4) $Δ G = 0 and reduction of the metal oxide$ 132. $Match List - I with List - II: Choose the most appropriate answer from the options given below :$ (1) $(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)$ (2) $(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)$ (3) $(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)$ (4) $(a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)$ 133. $The correct statement regarding the given Ellingham diagram is :$ (1) $At 1400ºC, Al can be used for the extraction of Zn from ZnO$ (2) $Coke cannot be used for the extraction of Cu from C u_{2} O$ (3) $At 800ºC, Cu can be used for the extraction of Zn from ZnO$ (4) $At 500ºC, coke can be used for the extraction of Zn from ZnO$ 134. $Extraction of gold and silver involves leaching with C N^{-} ion. Silver is later recovered by$ (1) $distillation$ (2) $zone refining$ (3) $displacement with Zn$ (4) $liquation(NEET2017)$ 135. $Native silver metal forms a water soluble complex with a dilute aqueous solution of NaCN in the presence of:$ (1) $nitrogen$ (2) $oxygen$ (3) $carbon dioxide$ (4) $argon$ 136. $In the leaching of alumina from bauxite, the ore expected to leach out in the process by reacting with NaOH is :$ (1) $\mathrm{TiO}_{2}$ (2) $F e_{2} O_{3}$ (3) $ZnO$ (4) $S i O_{2}$ 137. $Observe the following Ellingham diagram, and identify the incorrect statement regarding it$ (1) $At point ' A ' for the reduction of Al_{2} O_{3} by Mg, Δ G^{\circ} = 0$ (2) $Below 1673 K,Mg can reduce Al_{2} O_{3} to Al$ (3) $Below 1673 K, Al can reduce MgO to Mg$ (4) $Above 1673 K, Al can reduce MgO to Mg$ 138. $Among statements (a) - (d), the correct ones are (A) lime stone is decomposed to C a O during the extraction of iron from its oxides. (B) In the extraction of silver, silver is extracted as an anionic complex. (C) Nickel is purified by Mond's process. (D) Z r and T i are purified by Van Arkel method$ (1) $(a),(c) and (d) only$ (2) $(a) and (d) only$ (3) $(b),(c) and (d) only$ (4) $(a),(b),(c) and (d)$ 139. $Which of the following statements is not correct? 1.Reduction of alumina to give aluminium by magnesium is thermodynamically feasible. 2.The point of intersection of AlO_{3} and MgO curves in Ellingham diagram is below 1665 K . 3.Use of magnesium as reducing agent in metallurgy of aluminium is economical. 4.Ellingham diagram represents the graphical plot of Gibbs energy vs temperature for the formation of the oxides of common metals and reducing agents.$ (1) $1$ (2) $2$ (3) $3$ (4) $4$ 140. $The incorrect statement is$ (1) $bronze is an alloy of copper and tin$ (2) $cast iron is used to manufacture wrought iron$ (3) $German silver is an alloy of zinc, copper and nickel$ (4) $brass is an alloy of copper and nickel$ 141. $Copper matte is composed of \dots\dots\dots\dots..$ (1) $Cu_{2} S and Cu_{2} O$ (2) $Cu_{2} S and FeS$ (3) $CuFeS_{2} and Cu_{2} S$ (4) $CuS and FeS$ 142. $Hall-Heroult's process is given by:$ (1) $Cu^{2 +} (aq) + H_{2} (g) \to Cu (s) + 2 H^{+} (aq)$ (2) $Cr_{2} O_{3} + 2 Al \to Al_{2} O_{3} + 2 Cr$ (3) $2 Al_{2} O_{3} + 3 C \to 4 Al + 3 CO_{2}$ (4) $ZnO + C ⟶ Coke, 1673 K Zn + CO$ 143. $The composition of 'copper matte' is$ (1) $Cu_{2} S + FeS$ (2) $Cu_{2} S + Cu_{2} O$ (3) $Cu_{2} S + FeO$ (4) $Cu_{2} O + FeS$ 144. $The statement that is not correct is$ (1) $a furnace lined with haematite is used to convert cast iron to wrought iron.$ (2) $collectors enhance the wettability of mineral particles during froth flotation.$ (3) $in vapour phase refining, metal should form a volatile compound.$ (4) $copper from its low grade ores is extracted by hydrometallurgy.$ 145. $Calcium is obtained by$ (1) $reduction of calcium chloride with carbon$ (2) $electrolysis of molten anhydrous calcium chloride$ (3) $roasting of limestone$ (4) $electrolysis of solution of calcium chloride in H_{2} O . (1997)$ 146. $Identify the ore not containing iron.$ (1) $Limonite$ (2) $Siderite$ (3) $Carnallite$ (4) $Chalcopyrites$ 147. $Which of the following statements are correct related to metallurgy? (A) In electrolytic refining of copper, pure Cu is used as anode.(B) Zone refining is based on the principle that impurities are more soluble in the melt than in the solid state of the metal.(C) TiI_{4} upon heating will give pure Ti.(D) Very pure Zr may be obtained by galvanisation.(E) In copper smelting, hot air is used to convert to CuSO_{4} . The correct answer is$ (1) $(A), (B), (E)$ (2) $(B), (C)$ (3) $(B), (C), (D), (E)$ (4) $(B), (C), (D)$ 148. $The correct statement is :$ (1) $leaching of bauxite using concentrated NaOH solutiongives sodium aluminate and sodium silicate.$ (2) $the Hall-Heroult process is used for the production ofaluminium and iron.$ (3) $pig iron is obtained from cast iron.$ (4) $the blistered appearance of copper during the metallur-gical process is due to the evolution of CO_{2} .$ 149. $Ellingham diagram represents a graph of$ (1) $Δ G vs P$ (2) $Δ S vs P$ (3) $Δ G^{\circ} vs T$ (4) $Δ G vs T$ 150. $Cryolite is :$ (1) $Na3AlF6 and is used in the electrolysis of alumina for decreasing electrical conductivity.$ (2) $Na3AlF6 and is used in the electrolysis of alumina for lowering the melting point of alumina.$ (3) $Na3AlF6 and is used in the electrolytic purification of alumina.$ (4) $Na3AlF6 and is used in the electrolysis of alumina.$