General Principles of Isolation of Elements Test

Result

General Principles of Isolation of Elements Test - 2

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Sulphide ores are converted into oxides for the extraction of metals because

A
the sulphide ores are unstable

B
the formation of an oxide proceeds with the decrease in entropy

C
the formation of oxides is an exothermic process

D
the reduction of oxides is an endothermic process

Solution

The formation of metal oxides is an exothermic process, which makes it spontaneous at ordinary temperatures, but it proceeds with a decrease in entropy, because of which the Gibb's energy for the process becomes less negative with the increase in temperature and the process becomes less favourable.

Hence, at higher temperatures, it becomes easier to extract a metal from its oxides.
However, in case of sulphides, there is no such advantage. Hence, sulphides are converted into oxides.
Question 2
1 / -0

Fluorspar in the electrolytic reduction of alumina is dissolved in fused cryolite (Na₃AlF₆)

A
to lower the temperature of the melt and to make fused mixture very conducting

B
to decrease the rate of oxidation of carbon at the anode

C
to serve as a catalyst

D
to increase the fluidity of the electrolyte

Solution

CaF₂is added to maintain the fluidity of the mass, so that the molten aluminium metal sinks to the bottom of the electrolytic cell, from where it is collected through the tap hole.
Question 3
1 / -0

Blister copper is

A
an alloy of copper

B
pure copper

C
an ore of copper

D
partially pure copper

Solution

Blister copper is the copper produced by smelting and is 96 to 99 percent pure (partially pure copper). The trapped bubbles of SO₂ give it a blistery surface, which is why it is called blister copper.
Question 4
1 / -0

Sphalerite and calamine are ores of

A
copper

B
zinc

C
calcium

D
aluminium

Solution

Calamine is ZnCO₃ and sphalerite is a sulphide of zinc with iron replacing zinc at some of the lattice points. The latter is the chief ore of zinc.
Question 5
1 / -0

During the extraction of Al, coke powder is spread over the molten electrolyte in order to

A
prevent the escape of heat from the surface

B
lower the melting point of Al₂O₃

C
compensate for the loss of the anode

D
Both (1) and (3)

Solution

The layer of coke spread on the electrolyte, serves as an insulator. It also to some extent compensates for the carbon lost from anode through oxidation by the oxygen discharged at the anode, as a product of electrolysis.
Question 6
1 / -0

Which of the following methods is used for refining silver metal, containing lead impurity?

A
Poling

B
Liquefaction

C
Cupellation

D
Zone refining

Solution

Cupellation is heating the impure metal in cupel which is a pan made of bone ash in a blast of air. The lead impurity escapes as its volatile oxide.
Question 7
1 / -0

There are some chemical methods involved during the refining of metals. These methods are:

(I) Liquation
(II) Distillation
(III) Cupellation
(IV) Zone refining

Which method(s) is/are used to extract silver from argentiferous lead?

A
Only (I)

B
Both (II) and (III)

C
Only (III)

D
Both (I) and (IV)

Solution

Ag from argentiferous lead is separated out by distillation method as it is volatile in nature. Ag is purified by cupellation process.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

General Principles of Isolation of Elements Test - 2

Result

General Principles of Isolation of Elements Test - 2

Score

-

Rank

-

SHARING IS CARING

Question 1

the sulphide ores are unstable

the formation of an oxide proceeds with the decrease in entropy

the formation of oxides is an exothermic process

the reduction of oxides is an endothermic process

Solution

Question 2

to lower the temperature of the melt and to make fused mixture very conducting

to decrease the rate of oxidation of carbon at the anode

to serve as a catalyst

to increase the fluidity of the electrolyte

Solution

Question 3

an alloy of copper

pure copper

an ore of copper

partially pure copper

Solution

Question 4

copper

zinc

calcium

aluminium

Solution

Question 5

prevent the escape of heat from the surface

lower the melting point of Al2O3

compensate for the loss of the anode

Both (1) and (3)

Solution

Question 6

Poling

Liquefaction

Cupellation

Zone refining

Solution

Question 7

Only (I)

Both (II) and (III)

Only (III)

Both (I) and (IV)

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.

lower the melting point of Al₂O₃