d and f Block Elements

JEE Chemistry · 278 questions · Page 23 of 28 · Click an option or "Show Solution" to reveal answer

Q221

In the extraction of copper from its sulphate ore, metal is finally obtained by the oxidation of cuprous sulphide with :

A Fe2O3

B Cu2O

C SO2

D CO

Correct Answer

Option B

Solution

2Cu2S + 3O2 $\to$ 2Cu2O + 2SO2 2Cu2O + Cu2S $\to$ 6Cu + SO2 It is a example of auto reduction.

First a part of sulphide ore is converted into oxide which then reacts with remaining sulphide to give the metal.

Q222

The correct statement is :

A zincite is a carbonate ore.

B Sodium cyanide cannot be used in the metallurgy of silver.

C aniline is a froth stabilizer.

D zone refining process is used for the refining of titanium.

Correct Answer

Option C

Solution

Zincite is ZnO.

Sodium cyanide(AgCN) is used in Macarthur-forest Cyanide Process whre Ag is leached by dilute solution of NaCN.

Aniline is used as froth stabilizer in Froth flotation process.

Titanium is refined by Van Arkel method.

Q223

Assertion: For the extraction of iron, haematite ore is used. Reason: Haematite is a carbonate ore of iron.

A Both the assertion and reason are correct and the reason is the correct explanation for the assertion.

B Only the reason is correct.

C Both the assertion and reason are correct, but the reason is not the correct explanation for the assertion.

D Only the assertion is correct.

Correct Answer

Option D

Solution

For the extraction of iron, haematite ore in used. Haematite = Fe2O3 which is a oxide ore not carbonate ore.

Q224

The one that is not a carbonate ore is :

A siderite

B bauxite

C malachite

D calamine

Correct Answer

Option B

Solution

Bauxite = AlOx. (OH)3–2x Calamine = ZnCO3 Siderite = FeCO3 Malachite = CuCO3. Cu(OH)2

Q225

The Mond process is used for the

A Extraction of Zn

B extraction of Mo

C Purification of Zr and Ti

D Purification of Ni

Correct Answer

Option D

Solution

Mond process is used for purification of Ni.

Q226

With respect to an ore, Ellingham diagram helps to predict the feasibility of its.

A Electrolysis

B Thermal reducation

C Vapour phase refining

D Zone refining

Correct Answer

Option B

Solution

Ellingham diagram gives idea that which sustance or metal is suitable for thermal reduction of oxide.

Q227

The ore that contains both iron and copper is :

A Copper Pyrites

B Malachite

C Dolomite

D Azurite

Correct Answer

Option A

Solution

Copper pyrites : CuFeS2 Malachite : CuCO3 . Cu(OH)2 Azurite : 2CuCO3 . Cu(OH)2 Dolomite : CaCO3 . MgCO3

Q228

An Ellingham diagram provides information about :

A the temperature dependence of the standard Gibbs energies of formation of some metal oxides

B the pressure dependence of the standard electrode potentials of reduction reactions involved in the extraction of metals

C the conditions of pH and potential under which a species is thermodynamically stable

D the kinetics of the reduction process

Correct Answer

Option A

Solution

An Ellingham diagram provides information about, the temperature dependence of the standard gibbs energies of formation of some metal oxides.

Q229

Among statements (a) - (d), the correct ones are (a) Lime stone is decomposed to CaO 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) Zr and Ti are purified by Van Arkel method.

A (a), (c) and (d) only

B (c) and (d) only

C (b), (c) and (d) only

D (a), (b), (c) and (d)

Correct Answer

Option D

Solution

(a) CaCO3

\overset{\Delta}\longrightarrow

CaO + CO2 {In Blast furnace} (b) In extraction of silver, silver is extracted as an anionic complex [Ag(CN)2]–.

Ag/Ag2S + CN- $\to$ [Ag(CN)2] – (c) Ni is purified by mond's process Ni + 4CO

\overset{{330 - 350K}}\longrightarrow

Ni(CO)4 Ni(CO)4

\overset{{450 - 470K}}\longrightarrow

Ni + 4CO (d) Zr and Ti are purified by van arkel method

Q230

Cast iron is used for the manufacture of :

A wrought iron, pig iron and steel

B wrought iron and pig iron

C wrought iron and steel

D pig iron, scrap iron and steel

Correct Answer

Option C

Solution

Cast iron is used for manufacturing of wrought iron and steel.

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