MCQExams
0:0:1
CBSE
JEE
NTSE
NEET
Practice
Homework
×
CBSE Questions for Class 12 Engineering Chemistry General Principles And Processes Of Isolation Of Elements Quiz 8 - MCQExams.com
CBSE
Class 12 Engineering Chemistry
General Principles And Processes Of Isolation Of Elements
Quiz 8
Ellingham diagram represents change of:
Report Question
0%
$$\Delta G$$ with temperature
0%
$$\Delta H $$ with temperature
0%
$$\Delta G $$ with pressure
0%
($$\Delta G-T\Delta S$$) with temperature
Explanation
Ellingham
Diagram is diagrams which help us in predicting the feasibility of thermal
reduction of ore.
Ellingham diagram normally consists of plots of $$\Delta G$$ vs $$T$$ for the formation of oxides of common metals and reducing agents i.e., for the reaction shown below,
$$2xM{(s)}+O_2(g) \rightarrow 2M_xO$$
Hence, options A is the correct answer.
Which of the following statements is correct?
(i) Copper is extracted by hydrometallurgy from low-grade ores.
(ii) In the electrolytic reduction of alumina, graphite is acting as an anode and steel vessel with the lining of carbon acts as an anode.
(iii) In Hall-Heroult process, aluminium is obtained at anode and CO and $$CO_2$$ are produced at the cathode.
Report Question
0%
(i) only
0%
(i) and (ii) only
0%
(ii) and (iii) only
0%
All of these
Explanation
$$(i)$$ Copper is extracted by hydrometallurgy from low-grade ores. It is leached out using acid or bacteria. The solution containing $$Cu^{2+}$$ is treated with scrap iron or $$H_2$$.
$$Cu^{2+} (aq)+H_2 (g)\longrightarrow Cu (s)+2H^+ (aq)$$
$$(ii)$$ In the electrolytic reduction of alumina. The graphite act as anode and steel with a lining of carbon acts as an anode.
$$(iii)$$ The process of extracting Aluminium from Alumina $$(Al_2O_3)$$ by electrolysis is called Hall-Heroult process. In this process Aluminium is produced at cathode which is obtained by outlet, oxygen is released at an anode. It reacts with carbon of anode producing $$CO$$ and $$CO_2$$.
Which of the following is used as a method of purification for silicon?
Report Question
0%
Electrolytic refining
0%
Liquation
0%
Zone refining
0%
Distillation
Explanation
Zone refining is based on the principle that the impurities are more
soluble in the melt than in the solid state of the metal.
A mobile heater
surrounding the rod of impure metal is fixed at its one end
. The molten zone moves along with the heater which is
moved forward. As the heater moves forward,
the pure metal crystallizes out of the melt left
behind and the impurities pass on into the
adjacent new molten zone created by movement
of heaters.
The process is repeated several times
and the heater is moved in the same direction
again and again. Impurities get concentrated
at one end. This end is cut off.
This method is
very useful for producing semiconductor and
other metals of very high purity, e.g.,
germanium, silicon, boron, gallium, and indium.
Four metals and their methods of refinement are given
(i) $$Ni,\ Cu,\ Zr,\ Ga$$
(ii) Electrolysis, van Arkel process, zone refining, Mond's process
Choose the right method for each:
Report Question
0%
$$Ni:$$ Electrolysis, $$Cu:$$ van Arkel process, $$Zr:$$ Zone refining, $$Ga:$$ Mond's process
0%
$$Ni:$$ Mond's process, $$Cu:$$ Electrolysis, $$Zn:$$ van Arkel process, $$Ga:$$ Zone refining
0%
$$Ni:$$ Mond's process, $$Cu:$$ van Arkel process, $$Zr:$$ Zone refining, $$Ga:$$ Electrolysis
0%
$$Ni:$$ Electrolysis, $$Cu:$$ Zone refining, $$Zr:$$ van Arkel process, $$Ga:$$ Mond's process
Explanation
$$Ni$$ is refined by Mond's process.
$$Cu$$ is refined by Electrolysis.
$$Zn$$ is refined by Van Arkel process.
$$Ga$$ is refined by Zone refining.
In this method, a low melting metal like tin can be made to flow on a sloping surface. In this way it is separated from higher melting impurities. The method is known as:
Report Question
0%
distillation
0%
vapour phase refining
0%
liquation
0%
zone refining
Explanation
In Liquation a low melting metal like tin can be made to flow on a sloping surface. In this way it is separated from higher melting impurities.
Hence,option C is correct.
A number of elements are available in earth's crust but most abundant elements are _______.
Report Question
0%
$$Al$$ and $$Fe$$
0%
$$Fe$$ and $$Cu$$
0%
$$Cu$$ and $$Ag$$
0%
none of these
Explanation
Aluminium is the first most abundant metal element and Iron is the next element.
Match the column I with column II and mark the appropriate choice.
Column I
Column II
(A)
Van Arkel
(i)
$$Ni$$
(B)
Zone refining
(ii)
$$Ti$$
(C)
Mond process
(iii)
$$Ag$$
(D)
Cupellation
(iv)
$$Ge$$
Report Question
0%
(A) $$\rightarrow$$(i), (B)$$\rightarrow$$(ii), (C)$$\rightarrow$$(iii), (D) $$\rightarrow$$ (iv)
0%
(A) $$\rightarrow$$(iii), (B)$$\rightarrow$$(i), (C)$$\rightarrow$$(ii), (D) $$\rightarrow$$ (iv)
0%
(A) $$\rightarrow$$(ii), (B)$$\rightarrow$$(iv), (C)$$\rightarrow$$(i), (D) $$\rightarrow$$ (iii)
0%
(A) $$\rightarrow$$(iv), (B)$$\rightarrow$$(iii), (C)$$\rightarrow$$(i), (D) $$\rightarrow$$ (ii)
Explanation
Van Arkel process for refining $$Zr, Ti$$.
Zone refining for semiconductor like $$Ge$$.
Mond process for refining $$Ni$$.
Cupellation for refining noble metals like $$Ag, Au$$.
Zone refining is based on the principle that________.
Report Question
0%
impurities of low boiling metals can be separated by distillation
0%
impurities are more soluble in molten metal than in solid metal
0%
different component of a mixture are differently adsorbed on an adsorbent
0%
vapours of volatile compound can be decomposed in pure metal
Explanation
Zone refining is based on the difference in solubility of impurities in molten and solid state of the metal. Semi conductors like $$Si,Ge$$ and $$Ga$$ are purified by this method.
The method of zone refining of metals is based on the principle of:
Report Question
0%
greater mobility of pure metal than that of impurity.
0%
higher melting point of the impurity than that of pure metal
0%
all above are correct
0%
greater solubility of the impurity in the molten state than in the solid.
Explanation
Zone refining is based on the difference in solubility of impurities in molten and solid state of the metal. Semiconductor like $$Si,Ge$$ and $$Ga$$ are purified by this method.
Identify the oxide ore among the following :
Report Question
0%
Copper pyrites
0%
Copper glance
0%
Siderite
0%
Limonite
Explanation
Formula of Limonite is $$F_eO(OH)\cdot nH_2O$$. It is an oxide ore.
In case of Hall's process applied on reduction of $$Al_2O_3$$ to Al can be done by using:
Report Question
0%
Cathode - Al, Anode - Graphite
0%
Cathode - Graphite, Anode - Graphite
0%
Cathode - Graphite, Anode - Steel
0%
Cathode - Steel, Anode - Graphite
Explanation
Both are graphite
since in Hall's Process both the terminals are carbon content.
What is the main composition of matte?
Report Question
0%
$$CuS$$
0%
$$CuO$$
0%
$$Cu_{2}S$$
0%
$$Cu_{2}O$$
Explanation
Copper matte is a combination of copper sulphide and a small amount of iron sulphide. In the process of copper extraction matte is the stage subsequent to the final reduction process which involves converting it to crude copper.
The composition of copper in copper matte is:
Copper sulphide $$Cu_2S$$,
$$80-95$$%
The method of zone refining of metals is based on the principal of:
Report Question
0%
Greater mobility of the pure metal than that of the impurity
0%
Higher melting point of the impurity than that of the pure metal
0%
Greater noble character of the solid metal than that of the impurity
0%
Greater solubility of the impurity in the molten state than in the solid
Explanation
Zone refining is based on the difference in solubility of impurities in molten and solid-state of the metal. Semi-conductor like $$Si, Ge$$ and $$Ga$$ are purified by this method.
Hence, the correct option is $$D$$
Which of the following compound is used as froth stabliser?
Report Question
0%
Fatty acid
0%
Aniline
0%
Xanthates
0%
Phosphoric acid
Explanation
Here answer is option B
Aniline stabilize the froth before it is taken out for further treatment.
In this process, a suspension of a powdered ore is made with water. In this process, a suspension of a powdered ore is made with water. Collectors like pine oil, fatty acids and xanthates are added to it. Froth stabilizer like cresols, aniline stabilize the forth
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 $$Al = 27$$)
Report Question
0%
$$180$$ kg
0%
$$270$$ kg
0%
$$540$$ kg
0%
$$90$$ kg
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
Froth flotation process is based upon :
Report Question
0%
Magnetic property of gangue
0%
Specific gravity of ore particle
0%
Preferential wetting of ore particle by oil
0%
Preferential wetting of gangue particle by oil
Explanation
Froth flotation is a physicochemical process who's basic principle is to separate particles based on differences in surface wettability of those particles. Naturally hydrophobic (dislike water) particles (e.g. coal particles), become selectively attached to air bubbles and are carried to the surface of the pulp. So the correct option is C
Which of the following statements is correct wrt the following graph?
Report Question
0%
Below 1623 K, Mg reduces $$Al_2O_3$$
0%
Above 1623 K, Al reduces MgO
0%
Both (a) and (b) are correct
0%
Both (a) and (b) are wrong
Aluminothermy used for the spot welding of large iron structure is based on the fact that-
Report Question
0%
reaction between iron and oxygen is endothermic
0%
as compared to to Al, Fe has greater affinity for oxygen
0%
as compared to iron, Al has great affinity for oxygen
0%
reaction between Al and oxygen is endothermic
The process of carrying out the reduction of metal oxides by heating with coke is termed as :
Report Question
0%
Roasting
0%
Smelting
0%
Zone refining
0%
Ore dressing
Explanation
Smelting is the process where heat is applied to ore to extract the base metal, using a reducing agent. So, it is used to carry out reduction of metal oxides to metal by heating with coke.
Which of the following is colour blue ?
Report Question
0%
$$ CuF_2 $$
0%
$$ CuF $$
0%
$$ ZnF_2 $$
0%
$$ ZnCl_2 $$
Explanation
Colour of $$CuF_2$$ = White crystalline hygroscopic solid.
Colour of $$CuF$$ =White crystalline
Colour of $$ZnF2$$ =white
Colour of $$ZnCl2$$ =colourless or white. Copper hydroxide have blue colour
The electrolytes usually used in the electroplating of gold and silver, respectively are:
Report Question
0%
$$[Au(OH)_4]^- and [Ag(OH)_2]^-$$
0%
$$[Au(CN)_2]^- and [Ag(cl_2]^-$$
0%
$$[Au(NH)_3)_2]^+ and [Ag(CN)_2]^-$$
0%
$$[Au(CN)_2]^- and [Ag(CN)_2]^-$$
Explanation
The Anode
is
a bar of
silver
metal, and the
electrolyte
(the liquid in between the electrodes)
is
a solution of S
ilver
cyanide, $${[Ag{({CN})}_{2}]}^{-}$$, in water.
Gold plating is
done in much the same way, using a
gold
anode and an
electrolyte
containing G
old
cyanide, $${[Au{({CN})}_{2}]}^{-}$$.
Option D is correct
Identify $$x,\ y \ and \ z$$ for the following metallurgical process :
$$Metal\ sulphide\overset { x }{ \rightarrow } Metal\ oxide\overset { y }{ \rightarrow } Impure\ metal$$
$$x,\ y$$ and $$z$$ are respectively :
Report Question
0%
roasting, smelting, electrolysis
0%
roasting, calcination, smelting
0%
calcination, auto-reduction, basemerisation
0%
None of the above
Explanation
Roasting $$\rightarrow $$ It is a process in metallurgy
in which sulphide are is heated in
air and transforms into oxides.
Smelting $$\rightarrow $$ It is a process of extracting
a base metal from corresponding
metal oxides.
electrolysis $$ \rightarrow $$ It is used in metallurgical
process, such as in extraction or purification
of metals from ores or compounds.
Therefore, the correct option is A.
Which of the following is NOT calcination?
Report Question
0%
$$Fe(OH)_3.xH_2O\rightarrow Fe_2O_3+H_2O$$
0%
$$CuCO_3.Cu(OH)_2\rightarrow^ 2CuO+CO_2+H_2O$$
0%
$$CaCO_3\rightarrow^ CaO+CO_2$$
0%
$$(NH_4)_2CO_3\rightarrow^ 2NH_3+CO_2+H_2O$$
Explanation
Calcination is a process of heating to high temperature in air or oxygen, however calcination is also used to mean a thermal treatment process in the absence or limited supply of air or oxygen.
$$(NH_4)_2CO_3$$ is not an ore.so, it do not undergo calcination.
Which compound is used to separate two metal sulphide in forth flotation process :
Report Question
0%
$$ Na_2CO_3 $$
0%
KCI
0%
NaCN
0%
$$ (SCN)_2 $$
The combined state of metals are called:
Report Question
0%
Mineral
0%
Gangue
0%
Flux
0%
Native form
Explanation
The metal found in nature occur in the free or combined state it is generally known as pure metals. A native metal is a metal found in metallic state naturally. It can be in the pure form or in the form of an alloy.
$$Mineral:$$ Minerals are substances that are formed naturally in the earth. Minerals are usually solid, inorganic, have a crystal structure, and are formed naturally by geological process.
$$Gangue:$$ It is sand, rock and other impurities surrounding the minerals of interest in an ore. It is the combined state of the metal.
$$Flux:$$ It is a chemical cleaning, flowing or purifying agent. It is the substance added to the molten metals to bond with impurities that can be removed.
$$Native form:$$ Native element, any number of chemical elements that may occur in nature uncombined with other elements.
Hence, the correct option is B.
The above process is:
$$HgS\xrightarrow{O_2}HgS.HgO$$
$$\downarrow\Delta$$
$$Hg$$
Report Question
0%
auto oxidation
0%
self reduction
0%
thermal reduction
0%
none of the above
Explanation
Cinnabar ($$HgS$$), when heated with a current of $$O_2$$ gets reduced to $$Hg$$ without the need of any additional reducing agent. The process involved is known as self reduction
Tetrabromoethane on treatment with Zn gives :
Report Question
0%
ethyl bromide
0%
ethane
0%
ethene
0%
ethyne
All of the following statements are true about Ellingham diagram, except:
Report Question
0%
the graph for the formation of $$CO_2$$ from $$CO$$ and $$O_2$$ is a straight line with upward slope.
0%
the graph for the formation of $$CO$$ from carbon and oxygen is straight line almost parallel to temperature axis.
0%
the graph for the formation of $$ZnO$$ shows sudden change with positive slope.
0%
the graph for the formation of $$Ag_2O$$ is at upper part.
In the Hall-Heroult process, aluminium is formed at the cathode. The cathode is made out of:
Report Question
0%
platinum
0%
carbon
0%
pure aluminium
0%
copper
Explanation
The hall-heroult process is used for smelting of aluminium.
In the Hall-Heroult process, the cathode is made of carbon. Also, here anode is also made up of carbon.
Hence, the correct option is $$\text{B}$$
The bodies of aircraft are often made using aluminium.
Which two properties of aluminium make it suitable for this use?
Report Question
0%
property 1 - good conductor of electricity ; property 2- good conductor of heat
0%
property 1 - good conductor of electricity ; property 2- strong
0%
property 1 - good conductor of heat ; property 2- low density
0%
property 1 - strong ; property 2 - low density
Explanation
$$\text{It is more important that metal used in aircraft is strong enough and lighter too hence aluminium is used rather than iron in aircraft.}$$
Distillation under reduced pressure is used to purify liquids which:
Report Question
0%
are highly volatile
0%
have high boiling points
0%
are explosives
0%
decomposes below their boiling points
Explanation
Generally liquids that decomposes at their boiling point or before attaining boiling point requires distillation as a separation method.
In simple distillation of liquids, it involves simultaneously.
Report Question
0%
Vaporisation and condensation
0%
Heating and sublimation
0%
Vaporisation and sublimation
0%
Boiling and filtration
Explanation
Simple distillation happens through a process of heating and cooling liquids in order to separate and purify them. First, a liquid is heated, producing a vapor. Then, that vapor is cooled in a small tube called a condenser, in order to form a separate liquid. So, in simple distillation of liquids, it involves simultaneously vaporisation and condensation.
Match the refining methods (Column I) with metals (Column II).
Column I
(Refining methods)
Column II
(Metals)
(I)
Liquation
(a)
Zr
(II)
Zone Refining
(b)
Ni
(III)
Mond Process
(c)
Sn
(IV)
Van Arkel Method
(d)
Ga
Report Question
0%
(I) - (b); (II) - (c); (III) - (d); (IV) - (a)
0%
(I) - (b); (II) - (d); (III) - (a); (IV) - (c)
0%
(I) - (c); (II) - (a); (III) - (b); (IV) - (d)
0%
(I) - (c); (II) - (d); (III) - (b); (IV) - (a)
Explanation
Solution:- (D) (I) - (c); (II) - (d); (III) - (b); (IV) - (a)
Liquation is used for Sn.
Zone refining is used for Ga.
Mond's process is used for Ni.
Van arkel process is used for Zr.
Match the following:
(i)
Biodegradable polymer
(p)
3-Hydroxybutanoic acid
(ii)
Bakelite
(q)
Phenol
(iii)
Neoprene
(r)
2-chlorobuta-1, 3-diene
(iv)
Glyptal
(s)
phthalic acid
Report Question
0%
$$i - p, ii - q, iii - r, iv - s$$
0%
$$i - q, ii - p, iii - r, iv - s$$
0%
$$i - p, ii - q, iii - s, iv - r$$
0%
$$i - s, ii - r, iii - p, iv - q$$
Explanation
(i) PHBV (3-Hydroxybutanoic acid + 4-Hydroxypentanoic acid) is a biodegradable polymer.
(ii) Bakelite is synthesized from the monomer Phenol & Formaldehyde
(iii) 2-chlorobuta-1,3-diene is the monomer of
Neoprene.
(iv) Glyptal is synthesized from the condensation polymerization of Phthalic acid & Ethylene glycol.
Hence, the correct option is $$\text{A}$$
A copper coin was electroplated with Zn and then heated at high temperature until there is a change in colour. What will be the resulting colour ?
Report Question
0%
White
0%
Black
0%
Silver
0%
Golden
Explanation
Copper coin when electroplated with $$Zn$$ and then heated to high temperature, it forms brass.
Brass have golden colour.
Which represent incorrect matching of metals with their ores?
Report Question
0%
Mg - Chloride
Na - Chloride
Cu - Sulphide
Al - Silicate
0%
Mg - Carbonate
Na - Chloride
Cu - Sulphide
Al - Oxide
0%
Mg - Carbonate
Na - Carbonate
Cu - Oxide
Al - Phosphate
0%
Mg - Oxide,
Na - Chloride
Cu - Sulphide
Al - Oxide.
Explanation
Ores of the following metals are:
Mg-
Magnesite, MgCO
₃ (carbonate)
Na-Common salt, NaCl (chloride)
Cu- C
opper glance, Cu
₂S (sulphide)
Al- Bauxite, Al
₂O
₃ (oxide)
Thus, option B is the correct matching and rest all are incorrect.
Which of the following term is not related to Al extraction?
Report Question
0%
Serpek's process
0%
Hall-Heroult process
0%
Thermite process
0%
Hoop's process
Explanation
Hoop process: A molten alloy of copper, crude aluminium and silicon is used as the anode. It forms the lowermost layer in the cell.
Hall-Heroult process: This is the major industrial process of smelting aluminium.
Serperk process: The powdered bauxite is mixed with carbon and heated up to $$1800^oC$$ and a current of nitrogen is passed, aluminum nitride is obtained. Silica is converted in to silicon (Si).
Aluminium is used as a reducing agent in thermite process.
Find the correct match:
Report Question
0%
Azurite : $$CuCO_3. 2Cu(OH)_2$$
0%
Malachite : $$Cu(OH)_2. CuCO_3$$
0%
Anglesite : $$PbSO_4$$
0%
Chalcocite : $$Cu_2S$$
Explanation
Azurite is a copper carbonate hydroxide mineral with a chemical composition of $$Cu_3(CO_3)_2(OH)_2$$
.
The function of fractionating column is:
Report Question
0%
to separate the two components
0%
to provide greater, cooling surface to the vapours
0%
to kept the vapour pressure constant
0%
to avoid mixing of the vapours of two components
Explanation
Fractionating column is used in distillation. It helps in bringing the temperature of the vapours lower so that the liquid is attained in its pure form.
Froth flotation process is used for the
Report Question
0%
Oxide ores
0%
Sulphide ores
0%
Chloride ores
0%
All of these
Explanation
Only sulphide ores are concentrated by froth flotation process because pine oil selectively wets the sulphide ore and hence brings it to the froth. The sulphide ores preferably wetted by the oil and the gangue with the water.
The ore that is concentrated by froth flotation process
is:
Report Question
0%
Cinnabar
0%
Bauxite
0%
Malachite
0%
Zincite
Explanation
Ores which are concentrated by froth floatation process include Galena (PbS), zinc blende (ZnS) and cinnabar (HgS).
Hence , option A is correct.
Which of the following ores is/are sulphide ore(s)?
Report Question
0%
Galena
0%
Cinnabar
0%
Tinstone
0%
Copper pyrites
Explanation
Ex
planation:
The
sulphide minerals
are compounds of the metals with sulphur. Some ot the examples are:
Galena- ore of lead Formula is $$PbS$$
Cinnabar-ore of mercury
Formula is $$HgS$$
Copper pyrites-ore of copper. formula is $$CuFeS_2$$
Hence option A,B,D are correct.
Select the correct statements for Ellingham diagram:
Report Question
0%
The slope of the curves of the formation of metal oxide is +ve because $$\Delta G^0$$ becomes less negative or increases with the rise in temperature.
0%
Each curve is a straight line except when some change takes place in phase ($$s\rightarrow l \ or \ l \rightarrow g$$)
0%
Each curve is not a straight line except when some change takes place in phase ($$s \rightarrow l \ or \ l \rightarrow g$$)
0%
The slope of the curves of the formation of metal oxide is -ve because $$\Delta G^0$$ becomes less negative or increases with the rise in temperature.
For the reaction of FeO at the temperature corresponding to point D, which of the following statement is correct?
Report Question
0%
$$\Delta G $$ value for overall reduction reaction with carbon monoxide is zero.
0%
$$\Delta G $$ value for overall reduction reaction with a mixture of 1 mol of carbon and 1 mol of oxygen is positive
0%
$$\Delta G $$ value for overall reduction reaction with a mixture of 2 mol of carbon and 1 mol of oxygen is positive
0%
$$\Delta G $$ value for overall reduction reaction with carbon monoxide is negative
Which of the following statements is correct about the role of substances added in the froth floatation process?
Report Question
0%
Collectors enhance the non-wettability of the mineral particles.
0%
Collectors enhance the wettability of gangue particles.
0%
By using depressants in the process, two sulphide ores can be separated.
0%
Froth stabilizers decrease the wettability of gangue.
Explanation
Froth floatation method is used for the concentration of sulphide ores. The process is based on the preferential wetting properties with the frothing agent and water.
Sodium ethyl xanthate (collector) is added to enhance the non-wettability of sulphide ore particles, a
nd depressants are used to prevent certain types of particles from forming froth with the bubbles.
In the concentration of galena ore, sodium cyanide is added as a depressant for zinc sulphide $$(ZnS)$$. $$NaCN$$ forms a layer of zinc complex and deposits on the surface of $$ZnS$$ which prevents it from the formation of froth while $$PbS$$ forms a froth. Thus, by using depressants, two sulphide ores can be separated.
Hence, the correct statements are given in options (A) and (C).
Which of the following statements are correct?
Report Question
0%
A depressant prevents certain type of particle to come to the froth
0%
Copper matte contains $$Cu_2S $$ and $$ZnS$$
0%
The solidified copper obtained from reverberatory furnace has blistered appearance due to evolution of $$SO_2$$ during the extraction
0%
Zinc can be extracted by self-reduction
Explanation
Froth floatation method is used for the concentration of sulphide ores. D
epressants are used to prevent certain type of particles from forming the froth with the bubbles.
In the concentration of galena ore, sodium cyanide is added as a depressant for zinc sulphide $$(ZnS)$$. $$NaCN$$ forms a layer of zinc complex and deposits on the surface of $$ZnS$$ while prevents it for the formation of froth while $$PbS$$ forms a froth. Thus, by using depressants two sulphide ores can be separated.
The solidified copper obtained from reverberatory furnace has blistered appearance due to evolution of $$SO_2$$ during the extraction. Therefore, it is called blistered copper.
Zinc is extracted first by roasting and then by reduction with carbon.
Copper matte contains copper sulfide and iron sulfide.
Hence, the correct options are (A) and (C).
In the froth floatation process, zinc sulphide and lead sulphide can be separated by ____.
Report Question
0%
Using collectors
0%
Adjusting the proportion of oil to water
0%
Using depressant
0%
Using froth stabilizers
Explanation
Froth floatati
on method is used for the concentration of sulphide ores. The process is based on the preferential wetting properties with the frothing agent and water.
In the concentration of galena ore $$(PbS)$$, sodium cyanide is added as a depressant for zinc sulphide $$(ZnS)$$.
$$NaCN$$ forms a layer of zinc complex and deposits on the surface of $$ZnS$$ while prevents it for the formation of froth while $$PbS$$ forms a froth. Thus, by using depressants two sulphide ores can be separated.
Therefore, $$ZnS$$ and $$PbS$$ can be separated by using depressant and adjusting the proportion of oil to water.
Hence, the correct options are (B) and (C).
Which of the following ores are concentrated by froth floatation?
Report Question
0%
Haematite
0%
Galena
0%
Copper pyrites
0%
Magnetite
Explanation
Froth floatation is a physical method of separating minerals from the gangue. This method is used for concentration of sulphide ores. The method is based on the preferential wetting properties with the frothing agent and water.
This method is used to concentrate ores such as Zinc blende $$(ZnS)$$, galena $$(PbS)$$ and copper pyrites $$(CuFeS_2)$$.
Hence, the correct options are (B) and (C).
Pyrolusite is a/an :
Report Question
0%
oxide ore
0%
sulphide ore
0%
carbide ore
0%
not an ore
Explanation
Pyrolusite is an oxide ore of manganese. It is the most common manganese mineral with chemical formula $$MnO_{2}$$.
Hence, option (A) is correct.
Cassiterite is an ore of :
Report Question
0%
$$Mn$$
0%
$$Ni$$
0%
$$Sb$$
0%
$$Sn$$
Explanation
Cassiterite is a tin oxide mineral, $$SnO_{2}$$. It is the world's primary ore of tin. It is colourless when pure, but brown or black when iron impurities are present.
Hence, the correct option is (D).
0:0:1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
0
Answered
0
Not Answered
0
Not Visited
Correct : 0
Incorrect : 0
Report Question
×
What's an issue?
Question is wrong
Answer is wrong
Other Reason
Want to elaborate a bit more? (optional)
Practice Class 12 Engineering Chemistry Quiz Questions and Answers
<
>
Support mcqexams.com by disabling your adblocker.
×
Please disable the adBlock and continue.
Thank you.
Reload page
