Question Set A

TN 12th Standard Chemistry Metallurgy Previous Year Question Papers Study Material - QB365

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Questions:

Multiple Choice Question

30 x 1 = 30

Change in Gibbs free energy (ΔG) is related to the entropy change (ΔS) as ______.

(a)

\(\Delta \mathrm{G}=\Delta \mathrm{H}-\mathrm{T} \Delta \mathrm{S}\)

(b)

\(\Delta \mathrm{G}=\Delta \mathrm{H}+\mathrm{T} \Delta \mathrm{S}\)

(c)

\(\Delta \mathrm{G}=\frac{\Delta \mathrm{H}}{\Delta \mathrm{S}}\)

(d)

\(\Delta \mathrm{H}=\frac{\Delta \mathrm{G}}{\Delta}\)

Pyrolusite ore is concentrated by ________.

(a)

gravity separation

(b)

froth flotation

(c)

magnetic separation

(d)

both (a) and (c)

The process of converting hydrated alumina into anhydrous alumina is called ________.

(a)

Roasting

(b)

Smelting

(c)

Auto - reduction

(d)

Calcination

Which method of purification represented by the equation?
\(\text { Ti (impure) }+2 \mathrm{I}_{2} \stackrel{550 \mathrm{~K}}{\longrightarrow} \mathrm{Til}_{4} \stackrel{1800 \mathrm{~K}}{\longrightarrow} \mathrm{Ti} \text { (pure) }+2 \mathrm{I}_{2}\)

(a)

Cupellation

(b)

Zone refining

(c)

Van -Arkel method

(d)

Mond's process

Elements like silicon and Germanium to be used as a semiconductor is purified by _________.

(a)

Heating under vacuum

(b)

Van Arkel Method

(c)

Zone refining

(d)

Electrolysis

Which of the following is not true with respect to Ellingham diagram?

(a)

Free energy changes follow a straight line. Deviation occurs when there is a phase change.

(b)

The graph for the formation of CO₂ is a straight line almost parallel to free energy axis.

(c)

Negative slope of CO shows that it becomes more stable with increase in temperature.

(d)

Positive slope of metal oxides shows that their stabilities decrease with increase in temperature.

Which of the following reduction is not thermodynamically feasible?

(a)

\({ Cr }_{ 2 }{ O }_{ 3 }+2Al\longrightarrow { Al }_{ 2 }{ O }_{ 3 }+2Cr\)

(b)

\(\mathrm{Al}_2 \mathrm{O}_3+2 \mathrm{Cr} \longrightarrow \mathrm{Cr}_2 \mathrm{O}_3+2 \mathrm{Al}\)

(c)

\(3Ti{ O }_{ 2 }+4Al\longrightarrow 2A{ l }_{ 2 }{ O }_{ 3 }+3Ti\)

(d)

none of these

In the Ellingham diagram, for the formation of carbon monoxide________.

(a)

\(\left( \cfrac { \Delta { S }^{ 0 } }{ \Delta T } \right) \) is negative

(b)

\(\left( \cfrac { \Delta { G }^{ 0 } }{ \Delta T } \right) \) is positive

(c)

\(\left( \cfrac { \Delta { G }^{ 0 } }{ \Delta T } \right) \) is negative

(d)

initially \(\left( \cfrac { \Delta T }{ \Delta { G }^{ 0 } } \right) \) is positive, after 700^oC,\(\left( \cfrac { \Delta { G }^{ 0 } }{ \Delta T } \right) \) is negative

Which of the following plot gives Ellingham diagram

(a)

\(\Delta S \ \text{Vs} \ T\)

(b)

\(\Delta { G }^{ 0 }\ \text{Vs} \ T\)

(c)

\(\Delta { G }^{ 0 }\ \text{Vs} \ \frac { 1 }{ T } \)

(d)

\(\Delta { G }^{ 0 }\ \text{Vs} \ { T }^{ 2 }\)

10.

In the electrolytic refining of copper, which one of the following is used as anode?

(a)

Pure copper

(b)

Impure copper

(c)

Carbon rod

(d)

Platinum electrode

11.

The incorrect statement among the following is______.

(a)

Nickel is refined by Mond’s process

(b)

Titanium is refined by Van Arkel’s process

(c)

Zinc blende is concentrated by froth floatation

(d)

In the metallurgy of gold, the metal is leached with dilute sodium chloride solution

12.

Which of the following is used for concentrating ore in metallurgy?

(a)

Leaching

(b)

Roasting

(c)

Froth floatation

(d)

Both (a) and (c)

13.

The following set of reactions are used in refining Zirconium
\(Zr \text{(impure)}+2I_{ 2 }\overset { 523k }{ \longrightarrow } ZrI_{ 4 }\)
\({ ZrI }_{ 4 }\overset { 1800K }{ \longrightarrow } Zr \text{(pure)}+{ 2I }_{ 2 }\)This method is known as ______.

(a)

Liquation

(b)

Van Arkel process

(c)

Zone refining

(d)

Mond’s process

14.

Considering Ellingham diagram, which of the following metals can be used to reduce alumina?

(a)

(b)

(c)

(d)

15.

Extraction of gold and silver involves leaching with cyanide ion. silver is later recovered by_______.

(a)

Distillation

(b)

Zone refining

(c)

Displacement with zinc

(d)

liquation

16.

Cupellation is a process used for the refining of________.

(a)

Silver

(b)

Lead

(c)

Copper

(d)

iron

17.

Zinc is obtained from ZnO by________.

(a)

Carbon reduction

(b)

Reduction using silver

(c)

Electrochemical process

(d)

Acid leaching

18.

In the extraction of aluminium from alumina by electrolysis, cryolite is added to_______.

(a)

Lower the melting point of alumina

(b)

Remove impurities from alumina

(c)

Decrease the electrical conductivity

(d)

Increase the rate of reduction

19.

Which one of the following ores is best concentrated by froth – floatation method?

(a)

Magnetite

(b)

Haematite

(c)

Galena

(d)

Cassiterite

20.

Flux is a substance which is used to convert_______.

(a)

Mineral into silicate

(b)

Infusible impurities to soluble impurities

(c)

Soluble impurities to infusible impurities

(d)

All of these

21.

Electrochemical process is used to extract_______.

(a)

Iron

(b)

Lead

(c)

Sodium

(d)

silver

22.

Which one of the following is not feasible

(a)

Zn_(s) + Cu²⁺_(aq) \(\rightarrow\) Cu_(s) + Zn²⁺_(aq)

(b)

Cu_(s)+ Zn²⁺_(aq)\(\rightarrow\) Zn_(s) + Cu²⁺_(aq)

(c)

Cu_(s) + 2Ag⁺_(ag)\(\rightarrow\) 2Ag_(s) + Cu²⁺_(aq)

(d)

Fe_(s) + Cu²⁺_(aq) \(\rightarrow\) Cu_(s)+ Fe²⁺_(aq)

23.

Wolframite ore is separated from tinstone by the process of________.

(a)

Smelting

(b)

Calcination

(c)

Roasting

(d)

Electromagnetic separation

24.

Match items in column - I with the items of column – II and assign the correct code.

Column-I		Column-II
A.	Cyanide process	(i)	Ultrapure Ge
B	Froth floatation process	(ii)	Dressing of ZnS
C	Electrolytic reduction	(iii)	Extraction of Al
D	Zone refining	(iv)	Extraction of Au
		(v)	Purification of Ni

(a)

A	B	C	D
(i)	(ii)	(iii)	(iv)

(b)

A	B	C	D
(iii)	(iv)	(v)	(i)

(c)

A	B	C	D
(iv)	(ii)	(iii)	(i)

(d)

A	B	C	D
(ii)	(iii)	(i)	(v)

25.

Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true?

(a)

\(\Delta { G }_{ f }^{ 0 }\) of sulphide is greater than those for CS₂ and H₂S

(b)

\(\Delta { G }_{ r }^{ 0 }\) is negative for roasting of sulphide ore to oxide

(c)

Roasting of the sulphide to its oxide is thermodynamically feasible

(d)

Carbon and hydrogen are suitable reducing agents for metal sulphides

26.

Which of the metal is extracted by Hall-Heroult process?

(a)

(b)

(c)

(d)

27.

The metal oxide which cannot be reduced to metal by carbon is ________.

(a)

PbO

(b)

Al₂O₃

(c)

ZnO

(d)

FeO

28.

Which one of the following reaction represents calcinations?

(a)

\(2Zn+{ O }_{ 2 }\rightarrow 2ZnO\)

(b)

\(2ZnS+3O_{ 2 }\rightarrow 2ZnO+2SO_{ 2 }\)

(c)

\(MgCO_{ 3 }\rightarrow MgO+CO_{ 2 }\)

(d)

Both (a) and (c)

29.

Roasting of sulphide ore gives the gas (A).(A) is a colourless gas. Aqueous solution of (A) is acidic. The gas (A) is______.

(a)

CO₂

(b)

SO₃

(c)

SO₂

(d)

H₂S

30.

Bauxite has the composition ______.

(a)

Al₂O₃

(b)

Al₂O₃.nH₂O

(c)

Fe₂O₃.2H₂O

(d)

None of these

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Answers Key:

Multiple Choice Question

30 x 1 = 30

(a)
\(\Delta \mathrm{G}=\Delta \mathrm{H}-\mathrm{T} \Delta \mathrm{S}\)

(a)
gravity separation

(d)
Calcination

(b)
The graph for the formation of CO₂ is a straight line almost parallel to free energy axis.

(b)
\(\mathrm{Al}_2 \mathrm{O}_3+2 \mathrm{Cr} \longrightarrow \mathrm{Cr}_2 \mathrm{O}_3+2 \mathrm{Al}\)

(b)
\(\Delta { G }^{ 0 }\ \text{Vs} \ T\)

10.

(b)
Impure copper

11.

(d)
In the metallurgy of gold, the metal is leached with dilute sodium chloride solution

12.

(d)
Both (a) and (c)

13.

(b)
Van Arkel process

14.

15.

16.

(a)
Silver

17.

(a)
Carbon reduction

18.

(a)
Lower the melting point of alumina

19.

20.

(b)
Infusible impurities to soluble impurities

21.

22.

(b)
Cu_(s)+ Zn²⁺_(aq)\(\rightarrow\) Zn_(s) + Cu²⁺_(aq)

23.

(d)
Electromagnetic separation

24.

25.

(d)
Carbon and hydrogen are suitable reducing agents for metal sulphides

26.

(a)
Al

27.

(b)
Al₂O₃

28.

29.

30.

(b)
Al₂O₃.nH₂O

TN 12th Standard Chemistry Metallurgy Previous Year Question Papers Study Material - QB365 Set A

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Std: 12th Standard - Chemistry

chapter: Metallurgy - Previous Year Question Papers

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