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Occurrence of metals - class-XII

Attempted 0/82 Correct 0 Score 0

Pyrolusite is:

  1. a sulphide ore of $Mn$

  2. an oxide ore of $Mn$

  3. a carbide ore of $P$

  4. a chloride ore of $Zn$


Correct Option: B
Explanation:

Out of many minerals in which a metal may be found, only a few are viable to be used as source of that metal. Such minerals are known as ores.
Not all elements exists in pure states. Some elements exist in combined states.Among them the viable ones are there ores and the pure metal is obtained after undergoing various metallurgical processes.
Pyrolusite-($MnO _2$) is an oxide ore of Manganese.

Magnesium oxide is used for the lining in steel making furnace because:

  1. $MgO$ acts as an acidic flux to remove impurities of $Si,\ P$ and $S$

  2. $MgO$ acts as a basic flux to remove impurities of $Si,\ P$ and $S$

  3. $MgO$ acts as an oxidising agent to remove impurities of oxides

  4. $MgO$ does not react with any type of impurities


Correct Option: B
Explanation:

The impurities of the furnace are acidic. So to remove them, basic fluxes are added to remove it as slag.


Example: $MgO+SiO _2\rightarrow MgSiO _3$
                                                 slag

During the formation of the slag by the reaction of flux and impurities which of the following is an example of acidic and basic flux?
(i) $FeO + SiO _2\rightarrow FeSiO _3$
(ii) $SiO _2+MgO\rightarrow MgO\rightarrow MgSiO _3$

  1. (i) $SiO _2$ - Acidic flux (ii) $MgO$ - Basic flux

  2. (i) $SiO _2$ - Basic flux (ii) $MgO$ - Acidic flux

  3. (i) $SiO _2$ - Basic flux (ii) $MgO$ - Basic flux

  4. (i)$ SiO _2$ - Acidic flux (ii) $MgO$ - Acidic flux


Correct Option: A
Explanation:
i) $FeO+Si{ O } _{ 2 }\longrightarrow FeSi{ O } _{ 3 }$
In it $Si{ O } _{ 2 }$ is acidic flux and used to remove basic impurities.
ii) $Si{ O } _{ 2 }+MgO\longrightarrow MgSi{ O } _{ 3 }$
$Si{ O } _{ 2 }$ is acidic impurity. $MgO$ is basic flux used to remove $MgSi{ O } _{ 3 }$ as slag.

A number of elements are available in earth's crust but most abundant elements are _______.

  1. $Al$ and $Fe$

  2. $Fe$ and $Cu$

  3. $Cu$ and $Ag$

  4. none of these


Correct Option: A
Explanation:

Aluminium is the first most abundant metal element and Iron is the next element.

Impurities of sulphur, silicon, and phosphorus can be removed from cast iron by adding:

  1. carbon which reduces the impurities

  2. water which dissolves the impurities

  3. limestone which changes impurities into oxides and pass into slag

  4. iron oxide which reacts with impurities by forming slag


Correct Option: C
Explanation:

Flux is added to remove impurities as slag. So impurities like Sulphur, Silicon and Phosphorous are removed from case Iron by adding flux. Here flux is $CaC{ O } _{ 3 }$

Sulphur molecule exists as :

  1. $S _2$

  2. $S$

  3. $S _6$

  4. $S _8$


Correct Option: D
Explanation:

Sulphur molecule exists as $S _8$.

In the extraction of some metals from their ores, coke can be used as:

  1. Oxidizing agent

  2. Reducing agent

  3. Catalyst

  4. Flux


Correct Option: B
Explanation:

Metals below carbon in the reactivity series can be extracted using carbon. Carbon reduces the metal oxides that are extracted when heated. 


For example, the common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. 

Hence, option B is correct.

If an ore contains impurity of $SiO _2$, identify the appropriate flux for the removal of it:

  1. $MnO$

  2. $P _4O _{10}$

  3. $CO _2$

  4. $SO _2$


Correct Option: A
Explanation:

$MnO + SiO _2 \rightarrow MnSiO _3(Slag)$

Electrolytic reduction method is used for extraction?

  1. Highly electronegative elements

  2. Transition metals

  3. Highly electropositive elements

  4. Metalloids


Correct Option: C
Explanation:

Electrolytic reduction method is used for entraction of highly electropositive elements.

Example: $Na,K,Mg,Ca$ are obtained by electrolytic reduction processes.

In metallurgy, reduction is one of the major steps. However, all ores may not require an extra reducing agent, one such metallurgical operation is the extraction of?

  1. Fe from magnetite

  2. Sn from cassiterite

  3. Hg from cinnabar

  4. Zn from zinc blende


Correct Option: D

Reaction between which of the following results slag:

  1. Basic flux + basic impurity

  2. Acidic Flux + Basic impurity

  3. Acidic Flux + acidic impurity

  4. None of these


Correct Option: C

Which of the following metal occurs in native state?

  1. Ca

  2. Au

  3. Zn

  4. Al


Correct Option: B
Explanation:

Gold because of its inert nature does not combine with oxygen, hydrogen or humidity easily and thus occur in native state or free state.

The formula of the most abundant salt of sodium in nature is:

  1. $NaNO _{3}$

  2. $NaCl$

  3. $Na _{2}CO _{3}$

  4. $Na _{2}SO _{4}$


Correct Option: B
Explanation:

The most abundant salt of sodium in nature is sodium chloride (NaCl).

Gangue have :

  1. sand and soil

  2. silt

  3. gravel

  4. all of these


Correct Option: D
Explanation:

(i) Mineral is a naturally occurring substance that is solid and inorganic represented by chemical formula and has ordered structure. Minerals are differentiated based on their physical and chemical properties.
(ii) Ore is a type of rock that contains sufficient minerals with metals which are economically extracted by mining. Metal ores are generally oxides,sulphides,silicates. The ores are processed to extract metals.
(iii) Gangue are the impurities which are mixed closely with the ores. It is unwanted material which is of no market value and it is waste rock or mineral or sand etc.

The rocky material found with ores is known as............

  1. gangue

  2. stone

  3. sand

  4. none of these


Correct Option: A
Explanation:

Impurities like sand,stones and rocky material present with ores are removed by employing various processes either physical or chemical in many steps and these are known as gangue.

Various processes involved on the extraction of metals from their ores and refining are known as:

  1. concentration of ore

  2. enrichment of ore

  3. refining of ore

  4. metallurgy


Correct Option: D
Explanation:

To obtain a metal from its ore is called extraction of metal. The various process involved in the extraction of metals from the ores and refining are known as metallurgy.

Unwanted material with ore is called as ______ .

  1. Gangue

  2. Rust

  3. Slag

  4. Silica


Correct Option: A
Explanation:

Ores contain some impurities in the form of clay or rocky material known as gangue.

The process of extraction of metal from its ores, is known as :

  1. concentration

  2. calcination

  3. purification

  4. metallurgy


Correct Option: D
Explanation:

The process of extracting metals from their ores is called as metalurgy.The process employed in the extraction of the ore depends on the nature of the ore and the impurities present in it.The following are the basic steps for a metallurgical operation;

  1. Crushing and grinding of the ore.
  2. Concentration of the ore 
  3. Working of the ore 
  4. Purification or refining of the metal

The extraction of metals from their ores and then refining them for use is known as................. .

  1. metallurgy

  2. extacting

  3. metal technology

  4. none of these


Correct Option: A
Explanation:

Metallurgy is the science of extracting metals from their ores and modifying the metals for use. It is a commercial method.

Which of the following pairs is incorrect?

  1. Gneiss - Metamorphic

  2. Rock salt - Sedimentary

  3. Dolerite - Igneous

  4. Dolomite - Igneous


Correct Option: D
Explanation:

Dolomite is a sedimentary rock. Therefore, the incorrect match is option D

Process in which the extraction of metals from ores is called:

  1. metallurgy

  2. mining

  3. refining

  4. none of these


Correct Option: A
Explanation:

The process containing the extraction or refining of metals is known as metallurgy.

In metallurgy, the concentration of ore is followed by the dressing of ore.

  1. True

  2. False


Correct Option: B
Explanation:
Dressing of ore is followed by concentration of ore. 
Steps of metallurgy  are:
  • Crushing of the ore
  • Concentration of ore also known as Dressing of the ore
  • Conversion of concentrated ore to oxide 
  • Reduction of oxide to metal 
  • Refining of metal or Purification
Phosphorus mostly exists in free state.
  1. True

  2. False


Correct Option: B
Explanation:

The given statement is false.
Phosphorus does not exists in free state. It mostly exists in combined state. It occurs in the minerals of apetite family such as fluorapatite $\displaystyle Ca _9[PO _4] _6CaF _2$ which is main constituent of phosphate rocks. Phosphorous is essential constituent of animal and plant matter.

Which of the following oxides react to form slag in open hearth process?

  1. $CaO,CO$

  2. ${ P } _{ 2 }{ O } _{ 4 }, CaO$

  3. ${ P } _{ 2 }{ O } _{ 5 }, Si{ O } _{ 2 }$

  4. $CaO, { CO } _{ 2 }$


Correct Option: A
Explanation:
${CaCO _3} _{(s)}\longrightarrow CaO _{(s)}+{CO _2} _{(g)}$
$SiO _2+CaO \longrightarrow {CaSiO _3} _{(slag)}$
The calcium oxide formed by the decomposition reacts with various acidic impurities in the iron (mainly silica) to form slag which is essentially calcium silicate $(CaSiO _3)$ .

Which metal is obtained as by-products during metallurgy of Lithium ?

  1. Rubidium

  2. Caesium

  3. Both Rubidium and Caesium

  4. None of the above


Correct Option: B

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 :

  1. roasting, smelting, electrolysis

  2. roasting, calcination, smelting

  3. calcination, auto-reduction, basemerisation

  4. None of the above


Correct Option: A
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?

  1. $Fe(OH) _3.xH _2O\rightarrow Fe _2O _3+H _2O$

  2. $CuCO _3.Cu(OH) _2\rightarrow^ 2CuO+CO _2+H _2O$

  3. $CaCO _3\rightarrow^ CaO+CO _2$

  4. $(NH _4) _2CO _3\rightarrow^ 2NH _3+CO _2+H _2O$


Correct Option: D
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 of the following element is found in its native state?

  1. Silver

  2. Gold

  3. Sodium

  4. Both (A) and (B)


Correct Option: D
Explanation:

Silver and Gold occur in native state (free state). 

 
These elements have very low reactivity and are not attacked by oxygen or air, moisture, carbon dioxide or other non metals.

In the extraction of iron slag, which of the following is formed during extraction of iron?

  1. $Fe _3C$

  2. $FeSiO _3$

  3. $MgSiO _3$

  4. $CaSiO _3$


Correct Option: D
Explanation:

Reaction to form slag
$CaO+SiO _2\rightarrow CaSiO _3$ (slag)

Which of the following statements is correct regarding the slag formation during extraction of a metal like copper or iron?

  1. The slag is lighter and lower melting than the metal.

  2. The slag is heavier and lower melting than the metal.

  3. The slag is lighter and higher melting than the metal.

  4. The slag is heavier and higher melting than the metal.


Correct Option: A
Explanation:

Slag formed in extraction of metals are lighter and having low melting point than metal so they generally appear in upper layer of solutions.

The combined state of metals are called:

  1. Mineral

  2. Gangue

  3. Flux

  4. Native form


Correct Option: B
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.

Which is not a step of metallurgy ? 

  1. Reduction

  2. Roasting

  3. Corrosion

  4. Concentration of ore


Correct Option: C

Sulphide ores are common for metals:

  1. Ag, Cu and Pb

  2. Ag, Cu and Sn

  3. Ag, Mg and Pb

  4. none


Correct Option: A
Explanation:

  1. Argentite $Ag _2S$
  2.  Galena $PbS$
  3.  Chalcocite $Cu _2S$
  4.  Copper pyrite (chalco pyrite)$ [CuFeS _2]$
  5.  Cassiiterite $SnO _2$
  6.  Dolomite  [$ Ca Mg (CO _3) _2$]
  7.  Bauxite $Al(OH) _3$

∴ Sulphide containing ores are$ Ag, Cu, Pb.$


Option A is correct.

Which of following metal is extracted by electrometallurgical method-

  1. $Cu$

  2. $Fe$

  3. $Na$

  4. $Ag$


Correct Option: A,C
Explanation:

electrometallurgical method is used for the extraction of metals which are reactive in nature.

example. sodium,copper,aluminium and many more.

The pair that does NOT required calcination is :

  1. ZnO and $Fe _{2}O _{3}.xH _{2}O$

  2. $Fe _{2}O _{3}$ and $CaCO _{3}.MgCO _{3}$

  3. $ZnCO _{3}$

  4. ZnO and MgO


Correct Option: D

Which of the following is a basic carbonate mineral?
(i) Malachite  (ii) Dolomite  (iii) Azurite  (iv) Magnesite

  1. (i), (iii) and (iv)

  2. (II), (iii) and (iv)

  3. (i) and (iv)

  4. (iii) and (iv)


Correct Option: B

The process(es) by which lighter earthy particles are freed from the heavier particles using water is/are:

  1. Gravity separation

  2. Levigation

  3. Hydraulic washing

  4. Leaching


Correct Option: A,B,C
Explanation:

During concentration of ores, lighter earthy particles are freed from the heavier particles using water. This is carried out by gravity separation or hydraulic washing or levigation.
During leaching, the soluble material is extracted from insoluble material by dissolving out in a suitable solvent.

Which of the following mixture can be separated by magnetic separation?

  1. Iron filings, sand and iodine

  2. Common salt, sand and marbles

  3. Chalk powder, grain and chaff

  4. Stone, salt and water


Correct Option: A
Explanation:
For option A, the iron filling can be removed by using a magnet. an iron filling will be attracted by a magnet while water and iodine will not.

For option B, marbles can be separated by hand. Now add water salt will dissolve while sand will not. then separate the saltwater and sand.

For option C, winnowing can be used to separate chaff and grains.for chalk powder we can use filtration.

For option D, stone can be removed by handpicking, now water and salt can be separated by boiling the water. so water will evaporate leaving salt behind.

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

  1. $i - p, ii - q, iii - r, iv - s$

  2. $i - q, ii - p, iii - r, iv - s$

  3. $i - p, ii - q, iii - s, iv - r$

  4. $i - s, ii - r, iii - p, iv - q$


Correct Option: A
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 tin chloride $Q$ undergoes the following reaction (not balanced)
$Q + Cl^{-} \rightarrow X$
$Q + Me _{3}N \rightarrow Y$
$Q + CuCl _{2}\rightarrow Z + CuCl$
$X$ is monoanion having pyramidal geometry. Both $Y$ and $Z$ are neutral compounds. Choose the correct options(s)

  1. The central atom in $X$ is $sp^{3}$ hybridized

  2. There is a coordinate bond in $Y$

  3. The oxidation state of the central atom in $Z$ is $+2$

  4. The central atom in $Z$ has one lone pair of electrons


Correct Option: A,B
Explanation:

$\underset {(P)}{SnCl _{2}} + Cl^{-} \rightarrow \underset {(X)}{SnCl _{3}^{-}}$
$\underset {(P)}{SnCl _{2}} + Me _{3}N \rightarrow \underset {(Y)}{SnCl _{2} [N(CH _{3}) _{3}]}$
$\underset {(P)}{SnCl _{2}} + 2CuCl _{2}\rightarrow \underset {(Z)}{SnCl _{4}} + CuCl$.

Identify the ore not containing iron.

  1. Limonite

  2. Siderite

  3. Carnelite

  4. Chalcopyrites


Correct Option: C,D
Explanation:
Limonite, $Fe _2O _3.3H _2O$ and Silderite, $FeCO _3$ are iron ore.

Carnallite is an evaporite mineral, a hydrated potassium magnesium chloride with formula $KMgCl _3.6H _2O$. 

Chalcopyrite is the most important and major source of copper metal. It is widely spread copper–iron sulphide mineral with chemical formula, $CuFeS _2$.

Thus, Carnelite and chalcopyrite are not the ore of iron.

Hence, option C and D are correct.

Flux is used to remove :

  1. Tempering

  2. Annealing

  3. Hardening

  4. Remove the gangue


Correct Option: D
Explanation:

Flux is used to remove the gangue to form easily fusible slag.
$\underset {flux} {SiO _2} +\underset {gangue} {FeO}\rightarrow \underset {slag} {FeSiO _3}$

Which of the following metals are found in native state?


Ag, Pt, C, Si, N, O, Mg, Na, Pb

  1. Ag, Pt, C, N, O

  2. Ag, Pt, Mg

  3. Ag, Pt, Pb, Mg

  4. Ag, Pt


Correct Option: D
Explanation:

Ag and Pt are found in native (free) state.
Native silver usually occurs associated with coppr and gold, e.g., in alluvial sands.

CO is toxic because it forms complex with _________ in the blood.

  1. carbohydrate

  2. protein

  3. haemoglobin

  4. none of these


Correct Option: C
Explanation:

Carbon monoxide binds very strongly to the iron in hemoglobin. Once carbon monoxide attaches, it is very difficult to release. While breathing in carbon monoxide, it sticks to your hemoglobin and takes up all of the oxygen-binding sites. Eventually, blood loses all of its ability to transport oxygen and will cause unconsciousness.

During smelting, an additional substance is added which combines with impurities to form a fusible mass. The additional substance is called__________.

  1. Flux

  2. Slag

  3. Gangue

  4. Ore


Correct Option: A
Explanation:

In the process of smelting, inorganic chlorides, fluorides, limestone and other materials are designated as "fluxes" when added to the contents of a smelting furnace or a cupola for the purpose of purging the metal of chemical impurities such as phosphorus, and of rendering slag more liquid at the smelting temperature.

$SnO _2$ is reduced to metallic Sn on smelting oxide with anthracite and lime. In this, the function of lime is :

  1. it acts as a flux

  2. it removes acidic impurities as slag

  3. it removes ,basic impurities as slag

  4. it acts as a slag


Correct Option: A,B
Explanation:

In the smelting process the black Sn is mixed with anthracite and little limestone which acts as flux, now this mixture is heated to a degree centigrade of 1200-1300, as a result, $SnO _2$ is reduced to Sn. This crude is having many acid impurities which can be removed as slag.$SnO _2+2C \Rightarrow Sn+2C$.

Which of the following compounds are not called Thomas slag?

  1. Calcium silicate

  2. Calcium phosphate

  3. Barium phosphate

  4. Strontium silicate


Correct Option: A,C,D
Explanation:
Calcium phosphate($Ca _3(PO _4) _2O)$ is called Thomas slag and remaining calcium silicate, barium phosphate and strontium silicate are not Thomas slag.

Hence options A,C & D are correct.

Composition of azurite mineral is:

  1. $CuCO _3.CuO$

  2. $Cu(HCO _3) _2.Cu(OH) _2$

  3. $2CuCO _3.Cu(OH) _2$

  4. None of these


Correct Option: C
Explanation:

Azurite is one of the basic copper (II) carbonate minerals, the other being bright green malachite. Simple copper carbonate (CuCO3) is not known to exist in nature. Azurite has the formula $Cu(CO _3) _2(OH) _2$ with the copper (II) cations linked to two different anions, carbonate and hydroxide.

Hence the composition of azurite mineral is $2CuCO _3.Cu (OH) _2$

Predict the mode of occurrence of the following metals:

The correct answer is:

  1. $Na \rightarrow $ combined form

  2. $Fe \rightarrow $ combined form

  3. $Au \rightarrow $ combined form

  4. none of these


Correct Option: A
Explanation:

Sodium (alkali metal) is highly reactive and so, it occurs as a compound i.e. in combined form like NaCl.

${Ca _3(PO _4) _2}$ is :-

  1. Thomas slag

  2. Used in cement manufacturing

  3. Used in manufacturing of phosphorus fertilizer

  4. Used as a refactory material


Correct Option: A,B,C
Explanation:

${Ca _3(PO _4) _2}$ is called as Thomas slag and is used in cement manufacturing and manufacturing of phosphorus fertilizer,so options A,B & C are correct stetements.
Options A,B & C  are correct.

The most abundant metal in the earth crust is:

  1. Copper

  2. Silver

  3. Aluminium

  4. Silicon


Correct Option: C
Explanation:

Aluminum is the most abundant metal in the earth's crust but it is never found free in nature. Silicon is not a metal.

Which statement is correct?

  1. Gangues are carefully chosen to combine with the slag present in the ore to produce easily fusible flux to carry away the impurities

  2. Slags are carefully chosen to combine with the flux present in the ore to produce easily fusible gangue to carry away the impurities

  3. Gangues are carefully chosen to combine with the flux present in the ore to produce easily fusible slag to carry away the impurities

  4. Fluxes are carefully chosen to combine with the gangue present in the ore to produce easily fusible slag to carry away the impurities


Correct Option: D
Explanation:
Flux: The substance which is added to remove the gangue from the concentrated ore in its molten state is called Flux and the substance formed with flux is called Slag. Hence, fluxes have to be carefully chosen.

Acidic Flux
$SiO _2 + CaO \rightarrow CaSiO _3$
Acidic flux removes basic impurities.

Basic Flux
$SiO _2 + MgO \rightarrow MgSiO _3$
Basic flux removes acidic impurities

Silicon is the main constituent of _______.

  1. alloys

  2. rocks

  3. animals

  4. vegetables


Correct Option: B
Explanation:

Silicon is the most abundant element in the earth crust. It is found in rocks .


Therefore, the correct answer is $B$

Removal of impurities from ore is known as:

  1. Crushing 

  2. Concentration of ore

  3. Washing

  4. Grinding


Correct Option: B
Explanation:

The impurities present in the ore is known as gangue. The removal of impurities from the ore is known as concentartion of ore.

During the process of smelting, an additional substance is added which combines with impurities to form a fusible product in metal extraction. It is known as:

  1. Slag

  2. Mud

  3. Gangue

  4. Flux


Correct Option: D

Metallurgy is the process of:

  1. extracting metals from the ore

  2. roasting the ore

  3. extracting minerals from the ore

  4. adding carbon to the ore in blast furnace


Correct Option: A
Explanation:

The process of extraction, purification and refining of metals from ore is called metallurgy.

RCC is:

  1. the concrete having an iron framework inside it as a support

  2. the crushed cement in which more gravel is added

  3. prepared by adding calcium chloride to the limestone and calcium silicate

  4. none of the above


Correct Option: A
Explanation:

RCC is Reinforced concrete cement. It is a combination of concrete and steel to build a structure instead of using only concrete. Concrete is good in resisting compression and to gain resisting tension steel is added which has high tensile strength. To overcome the drawback of concrete, reinforced steel bars are used along with concrete.

The most abundant metal on the earth is:

  1. iron

  2. gold

  3. aluminium

  4. copper


Correct Option: C
Explanation:

Aluminium is the most abundant element in the earth's crust. It is most abundant in terms of quantity.

___________ metals occur free in nature.

  1. Alkali

  2. Noble

  3. Iron

  4. Aluminum


Correct Option: B
Explanation:

A noble metal is any metal that is found in its metallic form, either pure or alloyed, in nature. Over geological time scales, very few metals can resist natural weathering processes like oxidation, which is why generally only the less reactive metals such as gold and platinum are found as noble metals.

The flux used in the extraction of iron:

  1. limestone

  2. silica

  3. coconut oil

  4. feldspar


Correct Option: A
Explanation:

Coke, limestone flux, and iron ore are charged into the top of the furnace in a precise filling order which helps control gas flow and the chemical reactions inside the furnace. Hence, The flux used in the extraction of iron is limestone. 

Specific gravity of slag is always:

  1. much greater than the molten metal

  2. less than the molten metal

  3. same as molten metal

  4. more or less the metal depending on the metal


Correct Option: B
Explanation:

In blast furnace, products are collected at bottom. So, molten metal should be at bottom and slag is at up. So slag should have low density compared to molten metal.

Here an extraction process is given in steps. Identify the suitable ores corresponding to the process.
Pulverisation $\rightarrow$ Calcination $\rightarrow$ Smelting $\rightarrow$ Vacuum $\rightarrow$ Distillation

  1. Zinc blend

  2. Calamine

  3. Magnesite

  4. Zincite


Correct Option: A,B
Explanation:

Zinc Sulphide and Calamine responds for the process because, in $ZnS$, only zinc comes at smelting and after process, high purity comes after distillation. similar to Calamine, after distillation, the metal obtained is pure.

Gold does not occur in the combined form. It does not react with air or water. It is in the_______state.

  1. native

  2. combined

  3. original

  4. liquid


Correct Option: A
Explanation:

Gold is less reactive element. In electrochemical series, it is lower than Hydrogen. It doesn't react with anything. So it occurs as native metal.

Which one of the following is the chief ore of copper?

  1. galena

  2. copper pyrite

  3. siderite

  4. All of the above .


Correct Option: B
Explanation:

The principle ore of copper is copper pyrite $(CuFeS _2)$ and copper is extracted from this ore. 

Which of the following is an oxide ore?

  1. Malachite

  2. Haematite

  3. Chalcopyrite

  4. Zinc blende


Correct Option: B

The temperature of the slag zone in the metallurgy of iron using blast furnace is:

  1. 1200-1500$^0C$

  2. 1500-1600$^0C$

  3. 800-1000$^0C$

  4. more than 2000$^0C$


Correct Option: C
Explanation:

Slag is the fusible compound formed by the combination of flux and gangue.


$\underset{Flux}{CaO}+\underset{Gangue}{SiO _2} \rightarrow \underset{Slag}{CaSiO _3}$

At the temperature of the slag zone in the metallurgy of iron using blast furnace is $800^oC – 1000^oC$.

Option (C) is correct.

Handpicking method is effective in:

  1. solid mixtures

  2. liquid mixtures

  3. gaseous mixtures

  4. all of them


Correct Option: A
Explanation:

Hand picking is effective in solid mixtures as the impurities, that we want to separate are visible to eye.

Which metallurgy involves leaching?

  1. $Au$

  2. $Ag$

  3. Both (a) and (b)

  4. None of these


Correct Option: C
Explanation:

Gold and silver are extracted from their native ores by leaching. Leaching involves the treatment of the ore with suitable reagent as to make it soluble while impurities remain insoluble.

Stainless steel contains:

  1. $Fe,Ni,Cr$

  2. $Fe,Ni,Sn$

  3. $Fe,C,S$

  4. $Fe,P,Cr$


Correct Option: A
Explanation:

Iron, Nickel, Chromium

A solution is a homogeneous mixture of two or more substances. Which of the following is a solution?

  1. Milk

  2. Smoke

  3. Brass

  4. Face Cream


Correct Option: C
Explanation:

Alloys are the homogeneous mixture of metals or metals and non metals. Brass is an alloy of copper and zinc
Brass $Cu-70$%
$Zn-30$%
Alloys are solid-solid solution

Heating a pyrite in air to remove sulphur is known as:

  1. smelting

  2. roasting

  3. bessemerisation

  4. calcination


Correct Option: B
Explanation:

Roasting is a process of heating of sulphide ore to a high temperature in the presence of air. It is a step of the processing of certain ores.


Hence, option B is correct.

Which of the following is the ore of $Cu$?

  1. Ciderite

  2. Magnetite

  3. Calamine

  4. Malachite


Correct Option: D
Explanation:

Ore of copper is malachite $CuCO _{3}.Cu(OH) _{2}$.

The ore that can be concentrated by magnetic separation method is:

  1. bauxite $(Al _{2}O _{3}.xH _{2}O)$

  2. pyrolusite $(MnO _{2})$

  3. cuprite $(Cu _{2}O)$

  4. zincite $(ZnO)$


Correct Option: B
Explanation:

The ore that can be concentrated by magnetic separation method is pyrolusite $(MnO _{2})$.
In this method, the ferromagnetic and non-magnetic particles in the ore are separated by an electromagnetic separator.

The waste, or slag, that comes out at the bottom of a blast furnace for making iron from its ore, is no thrown away. It is used for making?

  1. Dental powder

  2. Roads

  3. Plastics

  4. Glass moulds


Correct Option: B
Explanation:

Solution:- (B) Roads

Slag is valuable raw material for preparation of macadam materials and mineral blinders serving as a base for asphalt concrete mixture and manufacturing of cement emulsions, which are widely used in road paving.

Match the columns.

List I List II
A. Bauxite $1.$ Lead
B. Haematite $2.$ Thorium
C. Galena $3.$ Aluminium
D. Monazite $4.$ Iron
  1. $A - 3, B - 1, C - 4, D - 2$

  2. $A - 4, B - 2, C - 1, D - 3$

  3. $A - 3, B - 4, C - 1, D - 2$

  4. $A - 2, B - 4, C - 3, D - 1$


Correct Option: C
Explanation:

Solution:- 

(A) Bauxite $\rightarrow \left( {Al} _{2}{O} _{3}.2{H} _{2}O \right)$ It is an ore of Aluminium containing $15-20 \%$ aluminium. $\rightarrow$ (3) Aluminium
(B) Haematite $\rightarrow \left({Fe} _{2}{O} _{3} \right)$ A reddish-black mineral consisting of ferric oxide. It is an important ore of iron. $\rightarrow$ (4) Iron
(C) Galena $\rightarrow \left( PbS \right)$ Galena, also called lead glance, is the natural mineral form of lead(II) sulfide. $\rightarrow$ (1) Lead
(D) Monazite $\rightarrow$ Monazite is an important ore for thorium, lanthanum, and cerium. It is radioactive due to the presence of thorium. $\rightarrow$ (2) Thorium

Pig iron can be converted into steel by removing a lot of carbon contained in it, in a/ an:

  1. electrolytic chamber

  2. bessemer converter

  3. blast furnace

  4. pyrite burner


Correct Option: B
Explanation:

Solution:- (B) bessemer converter

The Bessemer process was the first inexpensive industrial process for the mass production of steel from molten pig iron before the development of the open hearth furnace. The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron.

The removal of unwanted impurities by mechanical methods is known as:

  1. finishing

  2. ore dressing

  3. smelting

  4. none of these


Correct Option: B
Explanation:

As dressing is the process which have extraction and dressing. So, unwanted materials are removed through this method.

In manufacture of iron from Haematite, lime stone is added is act as:

  1. slag

  2. an oxidizing agent

  3. a reductant

  4. flux


Correct Option: D
Explanation:

Lime stone in the manufacture of Hematite ore is called flux. It removes unwanted material combining with gangue. 

Calcium silicate slag formed in extraction of iron :

  1. prevents the reoxidation of molten iron.

  2. catalyses the combustion of carbon

  3. reduces $CO _2$ to $CO$ at the bottom of the furnace

  4. is used in cement industry


Correct Option: A,D
Explanation:

Slag formed in extraction of iron is consists of $CaSiO _3$ which is further used for making cement.
Also, formation of this slag prevents the re-oxidation of molten iron.

Why do we need to separate different components of a mixture? Select the correct explanation from the following.

  1. To remove the unwanted impurities

  2. To obtained pure substances

  3. To separate, two different but useful components

  4. All of these


Correct Option: D
Explanation:

Mixtures have different physical and chemical properties compared with same metals. we need to separate different substances from mixtures as we want only useful substances and to obtain pure substances.

Matte contains mainly:

  1. $FeS$

  2. ${Cu} _{2}S$

  3. ${Cu} _{2}S$ and $FeS$

  4. ${Cu} _{2}S$ and ${Fe} _{2}{S} _{3}$


Correct Option: C
Explanation:

Matte contains mainly ${Cu} _{2}S$ and $FeS$. It also contains coke and sand. It is the molten metal obtained from the blast furnace.

Which element is present in Ruby as impurity?

  1. $Cu$

  2. $Cr$

  3. $Au$

  4. $Zn$


Correct Option: B
Explanation:

Chromium (Cr) metal is present in Ruby as an impurity. Ruby has pink to blood-red colour. It is a  gemstone. It is a variety of the mineral corundum (aluminium oxide).

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