Chapter 20

The INCORRECT statement is : [Main Sep. 06, 2020 (I)] (a) bronze is an alloy of copper and tin. (b) cast iron is used to manufacture wrought iron. (c) german silver is an alloy of zinc, copper and nickel. (d) brass is an alloy of copper and nickel.

The element that can be refined by distillation is : [Main Sep. 06, 2020 (II)] (a) nickel (b) zinc (c) tin (d) gallium

For a reaction, \(4 \mathrm{M}(\mathrm{s})+\mathrm{nO}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{M}_{2} \mathrm{O}_{\mathrm{n}}(\mathrm{s})\), the free energy change is plotted as a function of temperature. The temperature below which the oxide is stable could be inferred from the plot as the point at which : (a) the slope change from negative to positive (b) the free energy change shows a change from negative to positive value (c) the slop changes from positive to negative (d) the slop changes from positive to zero

Boron and silicon of very high purity can be obtained through : (a) liquation (b) zone refining (c) vapour phase refining (d) electrolytic refining

An Ellingham diagram provides information about: (a) the conditions of \(\mathrm{pH}\) and potential under which a species is thermodynamically stable. (b) the temperature dependence of the standard Gibbs energies of formation of some metal oxides. (c) the pressure dependence of the standard electrode potentials of reduction reactions involved in the extraction of metals. (d) the kinetics of the reduction process.

Cast iron is used for the manufacture of : [Main Sep. 02, 2020 (II)] (a) wrought iron and pig iron (b) pig iron, scrap iron and steel (c) wrought iron, pig iron and steel (d) wrought iron and steel

Among statements (1) - (4), the correct ones are : [Main Sep. 04, 2020 (I)] (1) Lime stone is decomposed to \(\mathrm{CaO}\) during the extraction of iron from its oxides. (2) In the extraction of silver, silver is extracted as an anionic complex. (3) Nickel is purified by Mond's process. (4) \(\mathrm{Zr}\) and Ti are purified by Van Arkel method. (a) \((1),(2),(3)\) and (4) (b) (1), (3) and (4) only (c) (2), (3) and (4) only (d) (3) and (4) only

The purest form of commercial iron is: (a) pig iron (b) wrought iron (c) cast iron (d) scrap iron and pig iron

The metal that cannot be obtained by electrolysis of an aqueous solution of its salts is: [Main 2014] (a) \(\mathrm{Ag}\) (b) \(\mathrm{Ca}\) (c) \(\mathrm{Cu}\) (d) \(\mathrm{Cr}\)

Among the reactions (a) - (d), the reaction(s) that does/do not occur in the blast furnace during the extraction of iron is/are: (a) \(\mathrm{CaO}+\mathrm{SiO}_{2} \rightarrow \mathrm{CaSiO}_{3}\) (b) \(3 \mathrm{Fe}_{2} \mathrm{O}_{3}+\mathrm{CO} \rightarrow 2 \mathrm{Fe}_{3} \mathrm{O}_{4}+\mathrm{CO}_{2}\) (c) \(\mathrm{FeO}+\mathrm{SiO}_{2} \rightarrow \mathrm{FeSiO}_{3}\) (d) \(\mathrm{FeO} \rightarrow \mathrm{Fe}+\frac{1}{2} \mathrm{O}_{2}\) (a) (a) (b) (a) and (d) (c) (c) and (d) (d) (d)

Copper is purified by electrolytic refining of blister copper. The correct statement(s) about this process is(are) [Adv. 2015] (a) Impure Cu strip is used as cathode (b) Acidified aqueous \(\mathrm{CuSO}_{4}\) is used as electrolyte (c) Pure Cu deposits at cathode (d) Impurities settle as anode-mud

The refining method used when the metal and the impurities have low and high melting temperatures, respectively, is: [Main Jan. 07, 2020 (II)] (a) liquation (b) vapour phase refining (c) zone refining (d) distillation

Match the refining methods (Column I) with metals (Column II).. (I) Liquation (a) \(\mathrm{Zr}\) (II) Zone Refining (b) \(\mathrm{Ni}\) (III) Mond Process (c) Sn (IV) Van Arkel Method (d) Ga (a) (I) \(-(\mathrm{c}) ;(\mathrm{II})-(\mathrm{a}) ;(\mathrm{III})-(\mathrm{b}) ;(\mathrm{IV})-(\mathrm{d})\) (b) (I) - (b); (II) - (c); (III) - (d); (IV) - (a) (c) (I) \(-(\mathrm{c}) ;(\mathrm{II})-(\mathrm{d}) ;(\mathrm{III})-(\mathrm{b}) ;(\mathrm{IV})-(\mathrm{a})\) (d) (I) - (b); (II) - (d); (III) - (a)l (IV) - (c)

The correct statement is : [Main April 10, 2019 (II)] (a) aniline is a froth stabilizer. (b) zincite is a carbonate ore. (c) sodium cyanide cannot be used in the metallurgy of silver. (d) zone refining process is used for the refining of titanium.

The ore that contains the metal in the form of fluoride is: (a) cryolite (b) malachite (c) magnetite (d) sphalerite

The one that is not a carbonate ore is: (a) malachite (b) calamine (c) siderite (d) bauxite

The Mond process is used for the : (a) purification of Ni (b) extraction of Mo (c) purification of \(\mathrm{Zr}\) and Ti (d) extraction of \(\mathrm{Zn}\)

In the Hall-Heroult process, aluminium is formed at the cathode. The cathode is made out of: [Main Jan. 12, 2019 (I)] (a) Pure aluminium (b) Carbon (c) Copper (d) Platinum

The ore that contains both iron and copper is: (a) copper pyrites (b) malachite (c) dolomite (d) azurite

In the leaching method, bauxite ore is digested with a concentrated solution of \(\mathrm{NaOH}\) that produces ' \(\mathrm{X}^{\prime}\). When \(\mathrm{CO}_{2}\) gas is passed through the aqueous solution of ' \(X\) ', a hydrated compound 'Y' is precipitated. ' \(X\) ' and ' \(Y\) ' respectively are. [Main Online April 15, 2018 (II)] (a) \(\mathrm{Na}\left[\mathrm{Al}(\mathrm{OH})_{4}\right]\) and \(\mathrm{Al}_{2}\left(\mathrm{CO}_{3}\right)_{3} \cdot \mathrm{xH}_{2} \mathrm{O}\) (b) \(\mathrm{Al}(\mathrm{OH})_{3}\) and \(\mathrm{Al}_{2} \mathrm{O}_{3} \cdot \mathrm{xH}_{2} \mathrm{O}\) (c) \(\mathrm{NaAlO}_{2}\) and \(\mathrm{Al}_{2}\left(\mathrm{CO}_{3}\right)_{3} \times \mathrm{xH}_{2} \mathrm{O}\) (d) \(\mathrm{Na}\left[\mathrm{Al}(\mathrm{OH})_{4}\right]\) and \(\mathrm{Al}_{2} \mathrm{O}_{3} \cdot \mathrm{xH}_{2} \mathrm{O}\)

Which one of the following ores is best concentrated by froth floatation method? [Main 2016] (a) Galena (b) Malachite (c)Magnetite (d) Siderite

Extraction of copper by smelting uses silica as an additive to remove : [Main Online April 10, 2016] (a) \(\mathrm{Cu}_{2} \mathrm{O}\) (b) \(\mathrm{FeS}\) (c) \(\mathrm{FeO}\) (d) \(\mathrm{Cu}_{2} \mathrm{~S}\)

In the context of the Hall - Heroult process for the extraction of Al, which of the following statements is false? \([\) Main 2015\(]\) (a) \(\mathrm{Al}^{3+}\) is reduced at the cathode to form \(\mathrm{Al}\) (b) \(\mathrm{Na}_{3} \mathrm{AlF}_{6}\) serves as the electrolyte (c) \(\mathrm{CO}\) and \(\mathrm{CO}_{2}\) are produced in this process (d) \(\mathrm{Al}_{2} \mathrm{O}_{3}\) is mixed with \(\mathrm{CaF}_{2}\) which lowers the melting point of the mixture and brings conductivity

Calamine is an ore of (a) zinc (b) aluminium(c) iron (d) copper

The form of iron obtained from blast furnace is: [Main Online April 9, 2014] (a) Steel (b) Cast Iron (c) Pig Iron (d) Wrought Iron

In Goldschmidt aluminothermic process which of the following reducing agents is used: [Main Online April 22, 2013] (a) calcium (b) coke (c) Al-powder (d) sodium

Sulfide ores are common for the metals (a) \(\mathrm{Ag}, \mathrm{Cu}\) and \(\mathrm{Pb}\) (b) \(\mathrm{Ag}, \mathrm{Mg}\) and \(\mathrm{Pb}\) (c) \(\mathrm{Ag}, \mathrm{Cu}\) and \(\mathrm{Sn}\) (d) \(\mathrm{Al}, \mathrm{Cu}\) and \(\mathrm{Pb}\)

In the cyanide extraction process of silver from argentite ore, the oxidising and reducing agents used are (a) \(\mathrm{O}_{2}\) and \(\mathrm{CO}\) respectively [2012] (b) \(\mathrm{O}_{2}\) and \(\mathrm{Zn}\) dust respectively (c) \(\mathrm{HNO}_{3}\) and \(\mathrm{Zn}\) dust respectively (d) \(\mathrm{HNO}_{3}\) and \(\mathrm{CO}\) respectively

Oxidation states of the metal in the minerals haematite and magnetite, respectively, are [2011] (a) II, III in haematite and III in magnetite (b) II, III in haematite and II in magnetite (c) II in haematite and II, III in magnetite (d) III in haematite and II, III in magnetite

Extraction of zinc from zinc blende is achieved by. (a) electrolytic reduction (b) roasting followed by reduction with carbon (c) roasting followed by reduction with another metal (d) roasting followed by self-reduction

Which ore contains both iron and copper? (a) Cuprite (b) Chalcocite (c) Chalcopyrite (d) Malachite

In the process of extraction of gold, Roasted gold ore \(+\mathrm{CN}^{-}+\mathrm{H}_{2} \mathrm{O} \stackrel{\mathrm{O}_{2}}{\longrightarrow}[X]+\mathrm{OH}^{-}\) \([X]+\mathrm{Zn} \longrightarrow[Y]+\mathrm{Au}\) Identify the complexes \([X]\) and \([Y]\) (a) \(X=\left[\mathrm{Au}(\mathrm{CN})_{2}\right]^{-}, Y=\left[\mathrm{Zn}(\mathrm{CN})_{4}\right]^{2-}\) (b) \(X=\left[\mathrm{Au}(\mathrm{CN})_{4}\right]^{3-}, Y=\left[\mathrm{Zn}(\mathrm{CN})_{4}\right]^{2-}\) (c) \(X=\left[\mathrm{Au}(\mathrm{CN})_{2}\right]^{-}, Y=\left[\mathrm{Zn}(\mathrm{CN})_{6}\right]^{4}\) (d) \(X=\left[\mathrm{Au}(\mathrm{CN})_{4}\right]^{-}, Y=\left[\mathrm{Zn}(\mathrm{CN})_{4}\right]^{2-}\)

Which of the following process is used in the extractive metallurgy of magnesium? [2002S] (a) fused salt electrolysis (b) self reduction (c) aqueous solution electrolysis (d) thermite reduction

Electrolytic reduction of alumina to aluminium by Hall-Heroult process is carried out [2000S] (a) in the presence of \(\mathrm{NaCl}\) (b) in the presence of fluorite (c) in the presence of cryolite which forms a melt with lower melting temperature (d) in the presence of cryolite which forms a melt with higher melting temperature

The chemical processes in the production of steel from haematite ore involve [2000S] (a) reduction (b) oxidation (c) reduction followed by oxidation (d) oxidation followed by reduction

The chemical composition of 'slag' formed during the smelting process in the extraction of copper is [2001S] (a) \(\mathrm{Cu}_{2} \mathrm{O}+\mathrm{FeS}\) (b) \(\mathrm{FeSiO}_{3}\) (c) \(\mathrm{CuFeS}_{2}\) (d) \(\mathrm{Cu}_{2} \mathrm{~S}+\mathrm{FeO}\)

In the commercial electrochemical process for aluminium extraction the electrolyte used is [1999-2 Marks] (a) \(\mathrm{Al}(\mathrm{OH})_{3}\) in \(\mathrm{NaOH}\) solution (b) an aqueous solution of \(\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}\). (c) a molten mixture of \(\mathrm{Al}_{2} \mathrm{O}_{3}\) and \(\mathrm{Na}_{3} \mathrm{AlF}_{6}\) (d) a molten mixture of \(\mathrm{AlO}(\mathrm{OH})\) and \(\mathrm{Al}(\mathrm{OH})_{3}\)

In the alumino-thermite process, aluminium acts as (a) an oxidizing agent (b) a flux (c) a reducing agent (d) a solder

In the metallurgy of iron, when limestone is added to the blast furnace, the calcium ion ends up in (a) slag (b) gangue (c) metallic calcium (d) calcium carbonate

Copper can be extracted from (a) Kupfernical (b) Dolomite (c) Malachite (d) Galena

In extractive metallurgy of zinc, partial fusion of \(\mathrm{ZnO}\) with coke is called .............. and reduction of the ore to the molten metal is called \(\ldots \ldots \ldots\) (smelting, calcining, roasting, sintering)

Casseterite is ore of

Which among the following statement(s) is(are) true for the extraction of aluminium from bauxite? [Adv. 2020] (a) Hydrated \(\mathrm{Al}_{2} \mathrm{O}_{3}\) precipitates, when \(\mathrm{CO}_{2}\) is bubbled through a solution of sodium aluminate. (b) Addition of \(\mathrm{Na}_{3} \mathrm{AlF}_{6}\) lowers the melting point of alumina. (c) \(\mathrm{CO}_{2}\) is evolved at the anode during electrolysis. (d) The cathode is a steel vessel with a lining of carbon.

The cyanide process of gold extraction involves leaching out gold from its ore with \(\mathrm{CN}^{-}\)in the presence of \(Q\) in water to form \(R\). Subsequently, \(R\) is treated with \(T\) to obtain \(\mathrm{Au}\) and \(Z\). Choose the correct option(s) (a) \(Q\) is \(\mathrm{O}_{2}\) (b) \(T\) is \(\mathrm{Zn}\) (c) \(Z\) is \(\left[\mathrm{Zn}(\mathrm{CN})_{4}\right]^{2-}\) (d) \(R\) is \(\left[\mathrm{Au}(\mathrm{CN})_{4}\right]^{-}\)

Extraction of copper from copper pyrite \(\left(\mathrm{CuFeS}_{2}\right)\) involves [Adv. 2016] (a) crushing followed by concentration of the ore by froth-flotation (b) removal of iron as slag (c) self-reduction step to produce 'blister copper' following evolution of \(\mathrm{SO}_{2}\) (d) refining of 'blister copper' by carbon reduction

Upon heating with \(\mathrm{Cu}_{2} \mathrm{~S}\), the reagent(s) that give copper metal is/are [Adv. 2014] (a) \(\mathrm{CuFeS}_{2}\) (b) \(\mathrm{CuO}\) (c) \(\mathrm{Cu}_{2} \mathrm{O}\) (d) \(\mathrm{CuSO}_{4}\)

The carbon-based reduction method is NOT used for the extraction of [Adv. 2013] (a) Tin from \(\mathrm{SnO}_{2}\) (b) Iron from \(\mathrm{Fe}_{2} \mathrm{O}_{3}\) (c) Aluminium from \(\mathrm{Al}_{2} \mathrm{O}_{3}\) (d) Magnesium from \(\mathrm{MgCO}_{3} \cdot \mathrm{CaCO}_{3}\)

Extraction of metal from the ore cassiterite involves (a) carbon reduction of an oxide ore (b) self-reduction of a sulphide ore (c) removal of copper impurity (d) removal of iron impurity

The major role of fluorspar \(\left(\mathrm{CaF}_{2}\right.\) ), which is added in small quantities in the electrolytic reduction of alumina dissolved in fused cryolite \(\left(\mathrm{Na}_{3} \mathrm{AlF}_{6}\right)\), is [1993-1 Mark] (a) as a catalyst (b) to make the fused mixture very conducting (c) to lower the temperature of the melt (d) to decrease the rate of oxidation of carbon at the anode.

Of the following, the metals that cannot be obtained by electrolysis of the aqueous solution of their salts are: [1990 - 1 Mark] (a) \(\mathrm{Ag}\) (b) \(\mathrm{Mg}\) (c) \(\mathrm{Cu}\) (d) \(\mathrm{Al}\) (e) \(\mathrm{Cr}\).