MCQ

MCQ 11 Mark

Choose the correct answer from the options given below :
The reason for using Aluminium in the alloy duralium is : ________ .

A
Aliminium is brittle
B
Aliminium gives strength
✓
Aluminium brings lightness
D
Aluminium lowers melting point

Answer

Correct option: C.

Aluminium brings lightness

Aluminium brings lightness
Alloy of aluminium, duralumin is used in making aircrafts as it is light and corrosion resistant.

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MCQ 21 Mark

Steel is an alloy of iron and : ________ .

A
Nickel
B
Zinc
✓
Carbon
D
Aluminium

Answer

Correct option: C.

Carbon

Steel is an alloy of iron and Carbon

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MCQ 31 Mark

Choose the correct answer:
Brass is an alloy of ________ .

A
Copper and tin
✓
Copper and zinc
C
Zinc and lead
D
Lead and tin

Answer

Correct option: B.

Copper and zinc

Brass is an alloy of: Copper and zinc

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MCQ 41 Mark

Choose the correct option:
A metallic oxide which cannot be reduced by normal reducing agents:

✓
Zinc oxide
B
Magnesium oxide
C
Copper(II) oxide
D
Iron(III) oxide

Answer

Correct option: A.

Zinc oxide

A metallic oxide which cannot be reduced by normal reducing agents is zinc oxide.

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MCQ 51 Mark

Choose the correct option :
The metal other than aluminium, which has a strong affinity for oxygen is:

A
Copper
✓
Magnesium
C
Silver
D
Gold

Answer

Correct option: B.

Magnesium

The metal other than aluminium which has a strong affinity for oxygen is magnesium.

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MCQ 61 Mark

Answer the following question with respect to Electrolytic Reduction of fused alimina. Find and mark the correct image with correct details of process.

Answer

A .

Explanation:
In the figure ' b ' electrode used for the extraction are aluminum rod (both as cathode and anode). Hence, in the above extraction the inactive electrode are carbon are used. In ' $c$ ' the electrolyte used is aluminium only whereas the complination cryolite fluorspar alumina and sprinkle powdered coke is used. In the figure 'd' extraction of Aluminium is done using Al rods as anode and Allining as cathode, Electrolyte used is only Alumina.
Hence answer ' a ' is correct option.

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MCQ 71 Mark

An alloy of Zn and Cu is dissolved in dil. HCl , hydrogen gas is evolved. In this evolution of gas

A
Only zinc reacts with dil. HCl
B
Only copper reacts with dil. HCl
C
Both zinc and copper react with dil. HCl
D
Only copper reacts with water

Answer

A. Only zinc reacts with dil. HCl
Explanation: When an alloy of zinc and copper is treated with dilute hydrochloric acid, only zinc reacts. Zinc, being more reactive, displaces hydrogen from the acid to form zinc chloride and hydrogen gas. Copper, less reactive, does not react with dilute hydrochloric acid under normal conditions.

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MCQ 81 Mark

During smelting, an additional substance is added which combines with impurities to form a fusible product known as

A
Slag
B
Mud
C
Gangue
D
Flux

Answer

A. Slag
Explanation: During smelting, flux is added to the ore to bind with impurities, forming slag, a fusible byproduct that separates easily from purified metal. This process enhances metal purity by efficiently removing unwanted components from the ore.

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MCQ 91 Mark

A non-metal used to preserve food material is:

A
Carbon
B
Phosphorus
C
Sulphur
D
Nitrogen

Answer

D. Nitrogen
Explanation: Nitrogen is used in food preservation as it displaces oxygen in packaging preventing oxidation and spoilage. This inert gas extends shelf life by maintaining freshness and preventing the growth of aerobic bacteria and fungi.

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MCQ 101 Mark

The bronze medals are made up of:

A
Cu and Zn
B
Zn and Ni
C
Cu and Sn
D
$Cu , Zn , Tn$

Answer

C. Cu and Sn
Explanation: Bronze is an alloy traditionally composed of copper ( Cu ) and $tin ( Sn )$. This combination provides the strength and corrosion resistance ideal for making durable items like medals, sculptures, and ancient tools.

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MCQ 111 Mark

Metals are refined by using different methods. Which of the following metals are refined by electrolytic refining?
(i) Au
(ii) Cu
(iii) Na
(iv) K

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

Answer

A. (i) and (ii)
Explanation: Electrolytic refining is a method used to purify metals by passing an electric current through a solution containing the metal. This process is particularly effective for metals like gold ( Au ) and copper (Cu), which can be refined to high purity levels. More reactive metals like sodium ( Na ) and potassium ( K ) are not refined by this method and require different refining techniques.

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MCQ 121 Mark

An alloy reacted with dilute hydrochloric acid to produce a gas which 'pops' a lighted splint. The residue reacted with dilute nitric acid to form a blue solution. Which one of the following pairs of metals is present in the alloy?

A
Copper and lead
B
Lead and magnesium
C
Copper and magnesium
D
Lead and zinc

Answer

C. Copper and magnesium
Explanation: The alloy contains copper and magnesium. Magnesium reacts with hydrochloric acid to release hydrogen gas. Copper does not react with dilute hydrochloric acid but reacts with dilute nitric acid to form a blue solution. confirming the presence of both metals in the alloy.

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MCQ 131 Mark

Which of the following oxide(s) of iron would be obtained on prolonged reaction of iron with steam?

A
FeO
B
$Fe _2 O _3$
C
$Fe _3 O _4$
D
$Fe _2 O _3$ and $Fe _2 O _4$

Answer

C. $Fe _3 O _4$
Explanation: Iron does not react with cold or hot water, but steam is passed over a red-hot iron, it reacts to form iron (II, III) oxide and hydrogen gas.
$3 Fe(s)+4 H_2 O(g) \rightarrow Fe_3 O_4(s)+4 H_2(g)$

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MCQ 141 Mark

The roosted metal oxides is reduced by reducing agent if present in forms oxides. Which of the following statement is correct w.r.t reduction and reducing agents.
P : Oxides of $K , Na , Ca , Mg$ cannot be reduced by $C , Co$ or $H _2$
Q: The highly reactive metal can be used as reducing agent.

A
Only P
B
Only Q
C
Neither P nor Q
D
Both P & Q

Answer

D. Both P & Q
Explanation: Oxides of highly active metals have great affinity towards oxygen and hence cannot be reduced by $C , Co$, and H .
The highly reactive metal can be used a reducing agent because they can displace metal of lower reactivity from thair compound.

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MCQ 151 Mark

When the surface of a metal is attached by air moisture or only other substance around it, the metal is said to corrode. The effect of corrosion on different metals leads to the formation of different compound.
Which of the following is a correct pairs of metal \& its coverded compound.
$P : Cu , Cu , CO _3$ (green)
$Q : Fe , Fe _2 O _3-x H _2 O$ (brown)
R: $Ag , Ag _2 S$ (black)

A
Only P
B
Only Q
C
Only R
D
Both Q & R

Answer

D. Both Q & R
Explanation: Iron get rusted forming hydrated exide while silver gets tarnished when exposed to the atmosphere which contains pollutant $H _2 S$ and forms black $Ag _2 S$. Copper when exposed to air and moisture it forms $Cu ( OH )_2$ and copper carbonate mixture $\left[ Cu ( OH )_2 \cdot 2 CuCO _3\right]$

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MCQ 161 Mark

Metal mirrors are composed of _______ alloy.

A
Duralumin
B
Brass
C
Magnalium
D
Alnico

Answer

C. Magnalium
Explanation: Metal Mirrors are composed of Magnalium alloy, which is an alloy of aluminium.

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MCQ 171 Mark

Out of all the alloys of aluminium, the one which shows the property of luster is:

A
Duralumin
B
Magnalium
C
Both (a) and (b)
D
Alnico

Answer

D. Alnico
Explanation : Alnico, an alloy of aluminium, shows the property of lustre; i.e., it shines very much.

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MCQ 181 Mark

What are the constituent elements of duralumin?

A
$Al , Cu , Mg$
B
Al and Mg
C
$Al , Cu , Mg$ and Mn
D
$Al , Cu$ and Mn

Answer

C. $Al , Cu , Mg$ and Mn
Explanation: Duralumin is $95 \%$ aluminium, $4 \%$ copper, $0.5 \%$ magnesium, and $0.5 \%$ manganese.

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MCQ 191 Mark

Which of the following statement is/are wrong out:
(i) Alloy is a homogeneous mixture
(ii) Alloy can be a mixture of metals and non-metals
(iii) The alloy increases the strength but decreases the corrosivity of the constituent element

A
Only (i)
B
(ii) and (iii)
C
(i) and (ii)
D
None of these

Answer

D. None of these
Explanation: Alloys are a homogeneous mixture of both metals and non-metals, and their introduction to the world was majority due to their property of increasing strength and decreasing corrosivity.

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MCQ 201 Mark

An alloy is a _______ mixture.

A
Homogeneous
B
Heterogeneous
C
Colloidal
D
None of these

Answer

A. Homogeneous
Explanation: An alloy is a homogeneous mixture of elements which is made by mixing two or more elements, at least one of which is a metal. Alloys are typically created to enhance the properties of the individual elements, such as improving strength, hardness, corrosion resistance, or other desired characteristics.

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MCQ 211 Mark

The following reactions occur in Hall and Heroult's experiment. The $X, Y$, and $Z$ here respectively are:
$Na_3 AlF_6-3 Na^{+}+Al^{3+}+X$
$CaF_2-Y+2 F^{-}$
$Al_2 O_3 \square 2 Al^{3+}+Z$

A
$F ^{-}, Cu ^{2+}$, and $O ^{-}$
B
$F ^{-}, Ca ^{2+}$, and $O ^{2-}$
C
$F ^{-}, Ca ^{+}$, and $O ^{2-}$
D
$F ^{-}, Cu ^{+}$, and $O ^{-}$

Answer

B. $F ^{-}, Ca ^{2+}$, and $O ^{2-}$
Explanation : When $Na _3 AlF _6$ dissociates into ions it produces $Na ^{+}, Al ^{3+}$ and $F ^{-}$ions. Similarly, Y is $Ca ^{2+}$ and Z is $O ^{2-}$.

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MCQ 221 Mark

The given picture represents which extraction process of Aluminium?

A
Baeyer's process
B
Hall and Heroult's process
C
Hoope's process
D
None of these

Answer

B. Hall and Heroult's process
Explanation: The given picture represents the method of electrolytic reduction of Aluminium from its ore. This process for the extraction of aluminium was developed by Hall and Heroult and this process is called as Hall and Heroult process.

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MCQ 231 Mark

Thick rods of which compounds are used as anode in the fused electrolyte in electrolytic reductions of Alumina?

A
Carbon coke
B
Cryolite
C
Fluorspar
D
Graphite

Answer

D. Graphite
Explanation: Thick rods made of graphite are typically used as anodes in the fused electrolyte in the electrolytic reduction of alumina (aluminum oxide) in the Hall-Héroult process.

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MCQ 241 Mark

The molten electrolyte is kept at _______ ${ }^{\circ} C$ by electrical heating in the electrolytic cell of Hall and Heroult's process.

A
900
B
950
C
980
D
1000

Answer

B. 950
Explanation: The molten electrolyte is kept at $950^{\circ} C$ by electrical heating in the electrolytic cell of Hall and Heroult's Process to purify Alumina.

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MCQ 251 Mark

Why is coke sprinkled over the surface of electrolytes?

A
It reduces heat loss.
B
It prevents the burning of anode.
C
Both (a) and (b)
D
It is used to increase the conductivity.

Answer

C. Both (a) and (b)
Explanation: Coke is often sprinkled over the surface of electrolytes in certain electrolysis processes for multiple reasons, including:
(a) It reduces heat loss by acting as a thermal insulator, helping to maintain high temperatures required for some electrolysis processes.
(b) It prevents the burning of the anode by forming a protective layer around it, preventing it from reacting with the high-temperature environment inside the electrolytic cell.

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MCQ 261 Mark

The voltage used in the electrolytic reduction of alumina is:

A
4 to 5 volts
B
6 to 7 volts
C
5 to 6 volts
D
7 to 8 volts

Answer

C. 5 to 6 volts
Explanation: The voltage used in the electrolytic reduction of alumina in the Hall-Herroult process typically ranges from 5 to 6 volts. A low voltage of 5 to 6 volts is used in the electrolytic reduction to avoid the decomposition of cryolite.

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MCQ 271 Mark

Which of the following is/are not used for reducing aluminium oxide?
(i) Carbon
(ii) Carbon monoxide
(iii) Hydrogen
(iv) Electrolytic reduction

A
(i), (ii) and (iii)
B
(i) and (ii)
C
(ii) and (iii)
D
All of these

Answer

A. (i), (ii) and (iii)
Explanation: Carbon, carbon monoxide, and hydrogen are not commonly used for reducing aluminum oxide; they are more commonly used in the reduction of other metal ores.
The reduction of aluminum oxide $\left( Al _2 O _3\right)$ to obtain aluminum metal is primarily achieved through the Hall-Héroult process, which involves electrolytic reduction.

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MCQ 281 Mark

The given picture describes Baeyer's process. At the precipitator, $Al ( OH )_3$ is obtained from which compound in the process?

A
$NaAlO _2$
B
$Al _2 O _3 \cdot 2 H _2 O$
C
$Al _2 O _3$
D
$Na _3 AlF _6$

Answer

A. $NaAlO _2$
Explanation: In the Bayer's process, aluminum hydroxide $\left( Al ( OH )_3\right)$ is obtained from the compound aluminum oxide $\left( Al _2 O _3\right)$, which is present in bauxite ore. So, aluminum hydroxide is obtained from aluminum oxide in the Bayer's process.

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MCQ 291 Mark

$Al ( OH )_3$ is heated at $1000^{\circ} C$ to produce:

A
$NaAlO _2$
B
$Al _2 O _3 \cdot 2 H _2 O$
C
$Al _2 O _3$
D
NaOH

Answer

C. $Al _2 O _3$
Explanation: Aluminium hydroxide is heated at $1000^{\circ} C$ to produce aluminium oxide, having molecular formula $Al _2 O _3$. The reaction is given as:
$2 Al(OH)_3 \rightarrow Al_2 O_3+3 H_2 O$

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MCQ 301 Mark

What are insoluble impurities called which are left behind in dissolving bauxite?

A
Red mud
B
Black mud
C
Alumina
D
Both (a) and (b)

Answer

A. Red mud
Explanation: Red mud consists of ferric oxide and sand. It is produced when bauxite dissolves in NaOH and produces useful compound sodium meta aluminate and impurities which are termed as red mud.

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MCQ 311 Mark

Complete the following reaction:
$NaAlO_2+2 H_2 O \rightarrow$

A
$Na _2 O + Al ( OH )_3$
B
$Na + Al _2 O _3$
C
$NaOH + Al ( OH )_3$
D
$NaOH + Al _2 O _3$

Answer

C. $NaOH + Al ( OH )_3$
Explanation: When sodium meta-aluminate is diluted with water and cooled at $50^{\circ} C$ then its hydrolysis produces sodium hydroxide and aluminium hydroxide as precipitate. The impurities get dissolve in NaOH . The chemical equation can be represented as:
$NaAlO _2+2 H _2 O \longrightarrow$$ \underset {\text {sodium hydroxide}}{ NaOH} + \underset {\text {Aluminium hydroxide}}{Al(OH)_3}$

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MCQ 321 Mark

Copper, Zinc and Tin are the metals alloyed to form.

A
Duralumin
B
Brass
C
Bronze
D
Solder

Answer

C. Bronze
Explanation: Bronze is an alloy with $80 \%$ of $Cu , 4 \% Zn$ and $16 \% Sn$ whereas duralumin contains $90 \% Al , 4 \%$ of Cu . Brass is a composition of Cu and Zn . Solder is alloyed with Pb and Sn .

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MCQ 331 Mark

What is the other name of NaOH which is employed in Baeyer's process?

A
Baking soda
B
Lime soda
C
Soda ash
D
Caustic soda

Answer

D. Caustic soda
Explanation: Sodium Hydroxide is a strong base with the common name of caustic soda. It is employed in Baeyer's process to obtain $NaAlO _2$ from bauxite.

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MCQ 341 Mark

The most abundant metal in the earth's crust is:

A
Iron
B
Aluminium
C
Calcium
D
Sodium

Answer

B. Aluminium
Explanation: Aluminium is the most abundant metal in Earth's crust, comprising about $8 \%$ of its weight. It's lightweight, corrosion-resistant, and used widely in industries like aerospace and packaging due to its desirable properties.

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MCQ 351 Mark

Identify the pairs of metals and their ores from the following.

Group A	Group B
(a) Bauxite	(i) Iron
(b) Calamine	(ii) Aluminium
(c) Magnetite	(iii) Zinc

A
(a)-(i), (b)-(ii), (c)-(iii)
B
(a)-(ii), (b)-(i), (c)-(iii)
C
(a)-(i), (b)-(iii), (c)-(ii)
D
(a)-(ii), (b)-(iii), (c)-(i)

Answer

D. (a)-(ii), (b)-(iii), (c)-(i)
Explanation: Bauxite is an ore of Aluminium, while calamine is zinc carbonate and Magnetite is triferric tetraoxide.

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MCQ 361 Mark

The compound that is, not a constituent of the electrolytic mixture used in the Hall-Heroult's process is:

A
$Al _2 O _3$
B
$NaAlO _2$
C
$Na _3 AlF _6$
D
$CaF _2$

Answer

B. $NaAlO _2$
Explanation: The Hall-Heroult process is used for extracting aluminium from aluminum oxide (alumina, $Al _2 O _3$ ). In this process, the electrolytic mixture which mainly consists of molten alumina and a mixture of cryolite $\left( Na _3 AlF _6\right)$ and other fluxes like calcium fluoride $\left( CaF _2\right)$ is used to lower the melting point of alumina and to improve the conductivity of the solution.

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MCQ 371 Mark

What is the chemical formula of Siderite?

A
$Fe _2 O _3 \cdot 3 H _2 O$
B
$FeCO _3$
C
$Fe _2 O _3$
D
$FeS _2$

Answer

B. $FeCO _3$
Explanation: Siderite is an ore of iron with the chemical formula, $FeCO _3$. Its chemical name is ferrous carbonate.

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MCQ 381 Mark

What is the chemical formula of Zincite?

A
ZnCO₃
B
ZnS
C
Zno
D
None of these

Answer

C. ZnO
Explanation: Zincite an ore of zinc with the chemical formula, ZnO. Its chemical name is zinc oxide.

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MCQ 391 Mark

What is the number of water of crystallisation in bauxite ore?

Answer

A. 2
Explanation: Bauxite is the chief ore of aluminium.
Chemical name of Bauxite is hydrated aluminium oxide.
Chemical formula is Al₂O₃.2H₂O
So, it has 2 molecules of water of crystallisation

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MCQ 401 Mark

The chemical name of bauxite ore is.

A
Aluminium oxide
B
Hydrated aluminium oxide
C
Sodium aluminium fluoride
D
None of these

Answer

B. Hydrated aluminium oxide
Explanation: Bauxite with a chemical formula, Al₂O₃.2H₂O is an ore of aluminium. Its chemical name is hydrated aluminium oxide.

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MCQ 411 Mark

A mineral from which the metal can be extracted economically and conveniently is known as:

A
Matrix
B
Ore
C
Flux
D
Alloy

Answer

B. Ore
Explanation: An ore is a mineral from which metal can be extracted profitably.

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MCQ 421 Mark

An unwanted earthly material associated with ore as impurity is known as:

A
Gangue
B
Flux
C
Froth
D
None of these

Answer

A. Gangue
Explanation: The unwanted material or impurities in the form of sand, rock or any other material that surrounds the mineral in an ore deposit is known as gangue.

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MCQ 431 Mark

An element of an inorganic compound found in nature is known as:

A
Mineral
B
Ore
C
Both (a) and (b)
D
None of these

Answer

A. Mineral
Explanation: Minerals are naturally occurring metal compounds that are combined with other materials such as dirt, sand and limestone rocks. They are helpful in obtaining metals for different purposes. Hence, an element of an inorganic compound found in nature is known as mineral.

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