12th Chemistry Solutions Chapter 1 Metallurgy

#1. The incorrect statement among the following is ………………

Nickel is refined by Monds process

ZinC blende is concentrated by froth floatation

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

Titanium is refined by Van Arkels process

#2. Electrochemical process is used to extract ………………

Sodium

Silver

Lead

Iron

#3. n the electrolytic refining of copper, which one of the following is used as anode?

Platinum electrode

Pure copper

Carbon rod

Impure copper

#4. Flux is a substance which is used to convert ………………

Mineral into silicate

Soluble impurities to infusible impurities

Infusible impurities to soluble impurities

All of these

#5. Which of the following is not truc with respect to Ellingham diagram?

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

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

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

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

#6. Which of the following reduction is not thermodynamically feasible?

Al₂O₃ → Cr₂O₃ + 2Al

none of these

3TiO₂ + 4Al → 2Al₂O₃ + 2Al

Cr₂O₃ → Al₂O₃ + 2Cr

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

Fe

Zn

Cu

Mg

#8. Which one of the following reaction represents calcination?

MgCO₃ → MgO + CO₂

2Zn + O₂ → 2ZnO

2ZnS + 3O₂ → 2ZnO + 2SO₂

Both (a) and (c)

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

SO₂

SO₃

H,S

CO₂

#10. Cupellation is a process used for the refining of ………………

Lead

Iron

Copper

Silver

#11. Wolframite ore is separated from tinstone by the process of ………………

Calcination

Roasting

Smelting

Electromagnetic separation

#12. Which of the metal is extracted by Hall-Herold process?

Zn

Cu

AI

Ni

#13. The following set of reactions are used in refining Zirconium

This method is known as

Zone refining

Liquation

Monds process

Van Arkel process

#14. Which of the following plot gives Ellingham diagram?

∆G° Vs T

∆G° Vs

∆S Vs T

∆G° Vs T

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

Cassiterite

Magnetite

Hematite

Galena

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

∆G_r° is negative for roasting of sulphide ore to oxide.

Roasting of the sulphide to its oxide is thermodynamically feasible.

∆G_f° of sulphide is greater than those for CS₂ and H₂S.

Carbon and hydrogen are suitable reducing agents for metal sulphides.

#17. Bauxite has the composition ………………

Al₂O₃

Al₂O₃.nH₂O

Fe₂O₃.2H₂O

None of these

#18. Which one of the following is not feasible?

Zn(s) + Cu²⁺(aq) → Cu(s) + Zn²⁺(aq)

Fe(s) + Cu²⁺(aq) → Cu(s) + Fe²⁺(aq)

Cu(s) + 2Ag⁺(aq) → Ag(s) + Cu²⁺(aq)

Cu(s) + Zn²⁺+(aq) → Zn(s) + Cu²⁺(aq)

#19. In the extraction of aluminium from alumina by electrolysis, cryolite is added to ………………

Increase the rate of reduction

Remove impurities from alumina

Lower the melting point of alumina

Decrease the electrical conductivity

#20. Extraction of gold and silver involves leaching with cyanide ion. Silver is later recovered by ………………

Distillation

Displacement with zinc

Zone refining

liquation

#21. The metal oxide which cannot be reduced to metal by carbon is ………………

Al₂O₃

ZnO

PbO

FeO

#22. In the Ellingham diagram, for the formation of carbon monoxide

initially `\left( \frac { \triangle T }{ \triangle { G }^{ 0 } } \right)` is positive, after 700°C, `\left( \frac { \triangle { G }^{ 0 } }{ \triangle T } \right)` is negative

`\left( \frac { \triangle { S }^{ 0 } }{ \triangle T } \right)` is negative

`\left( \frac { \triangle { G }^{ 0 } }{ \triangle T } \right)` is negative

`\left( \frac { \triangle { G }^{ 0 } }{ \triangle T } \right)`is positive

#23. Zinc is obtained from ZnO by ………………

Carbon reduction

Reduction using silver

Acid leaching

Electrochemical process

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

Froth floatation

Roasting

Both (a) and (c)

Leaching

12th Chemistry Solutions Chapter 1 Metallurgy – Online Test ( MCQ )