Chemistry · Science General

Metallurgical Processes

1,403 Questions

This section explores key metallurgical processes including ore concentration, pyrometallurgy, and metal refining. It also covers corrosion and the properties of refractory materials. These chemistry questions are relevant for engineering and science entrance tests.

Pyrometallurgy furnacesMetal refining techniquesCorrosion protection methodsOre concentrationAuto reduction process

Metallurgical Processes Questions

Multiple choice chemistry separation of matter crystals and crystallisation filtration and crystallisation other methods of separation

Arrange the following steps in crystallisation of copper sulphate.
A. Dissolve it in minimum amount of water.
B. Take some (approximately 5 g) impure sample of copper sulphate in a china dish.
C. Cover the solution with a filter paper and leave it undisturbed at room temperature to cool slowly for a day.
D. Evaporate water from the copper sulphate solution so as to get a saturated solution.
E. Filter the impurities out.

  1. A, C, B, D, E

  2. B, D, A, C, E

  3. B, A, D, E, C

  4. B, A, E, D, C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The correct order of steps in crystallisation of copper sulphate is B, A, D, E, C.
B. Take some (approximately 5 g) impure sample of copper sulphate in a china dish.
A. Dissolve it in minimum amount of water.
D. Evaporate water from the copper sulphate solution so as to get a saturated solution.
E. Filter the impurities out.
C. Cover the solution with a filter paper and leave it undisturbed at room temperature to cool slowly for a day.

Multiple choice chemistry basic analytical techniques partition coefficients solvent extraction separation methods

Mixture of ${\text{Al}}{\left( {{\text{OH}}} \right) _3}\,\,{\text{and}}\,\,{\text{Fe}}{\left( {{\text{OH}}} \right) _3}$ can be separated by

  1. ${\text{HCl}}\,$
  2. ${\text{N}}{{\text{H}} _{\text{4}}}{\text{OH}}\,$
  3. ${\text{NaOH}}$
  4. ${\text{HN}}{{\text{O}} _{\text{3}}}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Aluminum hydroxide is amphoteric and dissolves in strong acids like HCl, whereas ferric hydroxide is basic and also dissolves in strong acids. However, in the context of qualitative analysis, HCl is the standard reagent used to dissolve these hydroxides to separate them from other insoluble residues or to bring them into solution for further testing.

Multiple choice physics transfer of heat applications of heat conduction applications of insulation clothes - our necessity

The reason for providing copper bottoms in steel pans is :

  1. aesthet, carly looks good

  2. that copper is better conductor than steel

  3. that copper is not a good conductor than steel

  4. None of the above

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Copper bottoms are provided in steel pans because copper is better conductor of heat than steel.

Thermal conductivity of copper is highest ($38600w/mK$) while that of steel is lowest ($1245w/mK$).

Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

Iron glows in red colour when it is heated to very high temperature. The reason for this is :

  1. Heat we supply consumes red colour at high temperature

  2. Mechanical energy is being converted into heat energy

  3. All metals glow in red colour when heated

  4. Heat energy is being converted into light energy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Iron glows in red colour when it is heated to very high temperature cause heat energy is being converted into light energy.

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

(a) Roasting and calcination are the two processes to reduce the metal oxides to the respective metals.
(b) Magnesium is extracted from its ore by electrolytic reduction process.
(c) Cryolite is used in metallurgy of aluminium in order to increase the fusibility and conductivity
(d) I Hall's process bauxite is leached with the help of ${Na} _{2}{CO} _{3}$.
Which of the following options regarding the above statements is correct?

  1. a, b and c

  2. b, c and d

  3. c and d

  4. only a
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(b) Magnesium is extracted from its ore by electrolytic reduction process.
(c) Cryolite is used in metallurgy of aluminium in order to increase the fusibility and conductivity
(d) I Hall's process bauxite is leached with the help of ${Na} _{2}{CO} _{3}$. statements are correct. The concentrated ore is converted into metal oxide by calcination or roasting.

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

State the function of fluorspar in the metallurgy of aluminium.

  1. to increase conductivity

  2. to decrease conductivity

  3. to increase ductility

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pure alumina melts at about $2000^oC$ and is a bad conductor of electricity. If fused cryolite and fluorspar is added, the mixture melts at $900^0C$ and solution becomes a good conductor of electricity. 

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

The electrolyte used in electrolytic refining of impure aluminium is __________.

  1. $AI _2O _{3} + CaF _{2}$
  2. $Na _{3}AlF _{6} + CaF _{2}$
  3. $Al _2O _{3}, Na _{3}AlF _{6} and CaF _{2}$

  4. Any aluminium salt is molten state
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the metallurgy of aluminium, purified $Al _2O _3$ is mixed with $Na _3AlF _6$ or $CaF _2$ which lowers the melting point of the mix and brings conductivity.

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

In the electrolytic reduction of alumina, the electrolyte is covered with coke powder because, it __________.

  1. prevents oxidation of aluminium formed

  2. reacts with aluminium forming aluminium carbide

  3. prevents heat loss from the electrolyte

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The electrolytic mixture is sprinkled with coke to prevent the anode's oxidation by the oxygen evolved

Also, more material to the top of the anode is continuously added in the form of briquettes made from coke and pitch. The lost heat from the smelting operation is used to bake the briquettes into the carbon form required for reaction with alumina.
Therefore, $C$ is correct

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

The mass of carbon anode consumed (giving of carbon dioxide) in the production of $270 \ kg$ aluminium metal bum bauxite by Hall process is: (Atomic mass $Al = 27$)

  1. $180$ kg
  2. $270$ kg
  3. $540$ kg
  4. $90$ kg
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The chemical reaction for the Hall process is given by

$2Al _2O _3+3C\rightarrow 4Al+3CO _2$
Moles of aluminium produced$=\dfrac{270000}{27}=10000$
According to the reaction,
$10000 \; kg$ moles of aluminium can be produced by consuming $2500\times3=7500 \ moles $ of Carbon
Hence mass of carbon=$12\times 7500=90000\ g=90\ kg$

Therefore, D is the correct answer

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

In case of Hall's process applied on reduction of $Al _2O _3$ to Al can be done by using:

  1. Cathode - Al, Anode - Graphite

  2. Cathode - Graphite, Anode - Graphite

  3. Cathode - Graphite, Anode - Steel

  4. Cathode - Steel, Anode - Graphite
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Both are graphite 

since in Hall's Process both the terminals are carbon content.

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

Which of the following is / are involved in extraction of aluminium from bauxite?

  1. Electrolytic reduction

  2. Leaching

  3. Hyfrolysis

  4. Thermal decomposition
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The extraction of aluminium from bauxite involves the Bayer process (leaching) followed by the Hall-Heroult process, which is an electrolytic reduction of alumina. Since the question asks what is involved, and electrolytic reduction is the primary step for obtaining the metal, it is the most specific answer.

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

Aluminium is obtained by.

  1. heating AL2O with iron

  2. heating AL2O3 with coke

  3. electrolysing a solution of AL2O3 in molten cryolite

  4. electrolysing fused AICI3
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Aluminium is commercially produced via the Hall-Héroult process, which involves the electrolytic reduction of alumina (Al2O3) dissolved in molten cryolite (Na3AlF6) to lower its melting point and improve conductivity.

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

All the statements are correct.
(i) In gold Schmidt thermite process aluminium acts as a reducing agent
(ii) Mg is extracted by electrolysis of aq. solution of $MgCl _{2}$
(iii) Extraction of Pb is possible by smelting
(iv) Red bauxite is purified by Serpeck's  Method

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Option A & C are correct.
But Serpeck's  Method is used to purify white bauxite.
and
Mg is extracted by electrolysis of anhydrous $MgCl _{2}$.