d and f Block Elements — Page 14 | JEE Chemistry

Q131

Hall- Heroult's process is given by :

A Cu2+ (aq) + H2(g)

\to

Cu(s) + 2H+ (aq)

B Cr2O3 + 2AI

\to

Al2O3 + 2Cr

C 2Al2O3 + 3C

\to

4Al + 3CO2

D ZnO + C

\overset{{Coke,\,1673\,K}}\longrightarrow

Zn + CO

Correct Answer

Option C

Solution

In Hall-Heroult's process is given by At cathode :-

4Al_{\left( \ell \right)}^{3 + }{\mkern 1mu} {\mkern 1mu} + {\mkern 1mu} {\mkern 1mu} 12{e^ - }{\mkern 1mu} {\mkern 1mu} \,\mathrel{\mathop{\kern0pt\longrightarrow} \limits} \,\,4Al\left( \ell \right)

At Anode :-

6O_{\left( \ell \right)}^{2 - }\,\,\mathrel{\mathop{\kern0pt\longrightarrow} \limits} \,\,3{O_2}(g) + 12{e^ - }

3C + 3{O_2}\,\,\mathrel{\mathop{\kern0pt\longrightarrow} \limits} \,\,3C{O_2}\left( \uparrow \right)

Q132

The element that can be refined by distillation is :

A gallium

B nickel

C zinc

D tin

Correct Answer

Option C

Solution

Impure zinc is refined by distillation.

Q133

Match with .

List - I		List - II
(a)	Sodium Carbonate	(i)	Deacon
(b)	Titanium	(ii)	Castner-Kellner
(c)	Chlorine	(iii)	van-Arkel
(d)	Sodium hydroxide	(iv)	Solvay

A (a)

\to

(iv), (b)

\to

(iii), (c)

\to

(i), (d)

\to

(ii)

B (a)

\to

(iv), (b)

\to

(i), (c)

\to

(ii), (d)

\to

(iii)

C (a)

\to

(iii), (b)

\to

(ii), (c)

\to

(i), (d)

\to

(iv)

D (a)

\to

(i), (b)

\to

(iii), (c)

\to

(iv), (d)

\to

(ii)

Correct Answer

Option A

Solution

(a) Sodium carbonate is prepared by Solvay process (b) Titanium is refined by Van-Arkel process (c) Chlorine is prepared by Deacon process (d) Sodium hydroxide is prepared by Castner-Kellner process

Q134

The chemical that is added to reduce the melting point of the reaction mixture during the extraction of aluminium is :

A Cryolite

B Bauxite

C Calamine

D Kaolite

Correct Answer

Option A

Solution

Alumina is mixed with Na3AlF6 (Cryolite) and CaF2 to lower the melting point of mixture.

Q135

The role of depressants in 'Froth Flotation method' is to

A selectively prevent one component of the ore from coming to the froth.

B reduce the consumption of oil for froth formation.

C stabilize the froth.

D enhance non-wettability of the mineral particles.

Correct Answer

Option A

Solution

Depressant prevent one component from coming to the froth.

For eg., in Galena ore, the depressant (NaCN) prevents impurity (ZnS) from coming to the froth.

Q136

Refining using liquation method is the most suitable for metals with :

A Low melting point

B High boiling point

C High electrical conductivity

D Less tendency to be soluble in melts than impurities

Correct Answer

Option A

Solution

Refining using liquation method is the most suitable for metals with low melting point

Q137

The metal that is not extracted from its sulfide ore is :

A Aluminium

B Iron

C Lead

D Zinc

Correct Answer

Option A

Solution

Aluminium is not extracted from sulphide ore.

It is usually extracted from bauxite ore, leaching of bauxite ore is done followed by electrolytic reduction.

Q138

Which of the reaction is suitable for concentrating ore by leaching process ?

A

2 \mathrm{Cu}_{2} \mathrm{~S}+3 \mathrm{O}_{2} \rightarrow 2 \mathrm{Cu}_{2} \mathrm{O}+2 \mathrm{SO}_{2}

B

\mathrm{Fe}_{3} \mathrm{O}_{4}+\mathrm{CO} \rightarrow 3 \mathrm{FeO}+\mathrm{CO}_{2}

C

\mathrm{Al}_{2} \mathrm{O}_{3}+2 \mathrm{NaOH}+3 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{Na}\left[\mathrm{Al}(\mathrm{OH})_{4}\right]

D

\mathrm{Al}_{2} \mathrm{O}_{3}+6 \mathrm{Mg} \rightarrow 6 \mathrm{MgO}+4 \mathrm{Al}

Correct Answer

Option C

Solution

Leaching involves the treatment of ore with a suitable reagent so as it make it soluble while impurities remain insoluble.

$\mathrm{Al}_{2} \mathrm{O}_{3}+2 \mathrm{NaOH}+3 \mathrm{H}_{2} \mathrm{O} \rightarrow \underset{\text{Soluble complex}}{2 \mathrm{Na}\left[\mathrm{Al}(\mathrm{OH})_{4}\right]}$

Q139

The major component of which of the following ore is sulphide based mineral?

A Sphalerite

B Siderite

C Malachite

D Calamine

Correct Answer

Option A

Solution

Sphalerite $\to$

\mathrm{ZnS}

Calamine $\to$

\mathrm{ZnCO_3}

Malachite $\to$

\mathrm{CuCO_3.Cu(H)_2}

Siderite $\to$

\mathrm{FeCO_3}

Q140

Which of the following is used as a stabilizer during the concentration of sulphide ores?

A Cresols

B Xanthates

C Fatty acids

D Pine oils

Correct Answer

Option A

Solution

In the froth floatation process pine oils, fatty acids, and xanthates are collectors, and froth stabilizers cresols, and aniline are used.