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Alloys and their properties - class-XII

Description: alloys and their properties
Number of Questions: 54
Created by:
Tags: chemical bonding and structure states of matter chemistry elements and compounds
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Ornamental gold is an alloy of gold and silver.

  1. True

  2. False


Correct Option: A
Explanation:

Gold as pure metal is too soft on its own and is therefore hardened by the addition of alloying element like silver for ornamental purpose.
option A is correct.

Which of the following pair of elements form alloy?

  1. $Zn$ and $Pb$

  2. $Fe$ and $C$

  3. $Hg$ and $Ag$

  4. All of these


Correct Option: D
Explanation:
Alloys are formed by metals whose atomic radii not differ by more than $15 \%$ so that the atoms of one metal can easily take up the positions in the crystal lattice of the other.
Thus all of these will be the correct answer.

The mixture of two or more metals is called a/an _______ .

  1. solder

  2. mixture

  3. alloy

  4. amalgam


Correct Option: C
Explanation:

The mix of two or more metals is called an alloy. the various properties of metals can be unproved by mixing two or more metals.

The alloy steel used for making automobile parts and utensils is called

  1. nickel steel

  2. stainless steel

  3. tungsten steel

  4. chromium steel


Correct Option: A

An alloy which does not contain copper is:

  1. solder

  2. bronze

  3. brass

  4. bell metal


Correct Option: A
Explanation:

Solder- an alloy of tin $(Sn)$ and lead $(Pb)$
Bronze-an alloy of copper $(Cu)$ and tin $(Sn)$
Brass-an alloy of copper $(Cu)$ and Zinc $(Zn)$
Bell metal-an alloy of copper $(Cu)$ and tin $(Sn)$
Therefore option A is correct

Select the correct alternative for the preparation of steel:

  1. A - coal, B- limestone, C - iron ore

  2. A - coal, B - iron ore , C -limestone

  3. A - limestone, B - coal , C - iron ore

  4. A - iron ore, B -limestone , C - coal


Correct Option: D
Explanation:

Making iron is the first step of production of steel. Iron is usually made from iron ore,limestone and coal. Limestone is added to iron before entering the blast furnace. The limestone reacts with acidic impurities called slag and floats on top of the molten iron where it is skimmed off.

Element present in the stainless steel is ______________.

  1. Iron

  2. Chromium

  3. Nickel

  4. All of these


Correct Option: D
Explanation:

Stainless steel also known as inox steel. It is an alloy of steel (Iron and nickel) with chromium 10.5%. It does not corrode readily, rust or stain. There are different grades of stainless steel. It is used where both the properties of steel and corrosion resistance are required.

Mark the incorrect statement.
a) Alloys with required properties can be made.
b) Alloys have properties different from constituent metals.
c) Alloys can never have carbon in it.
d) Alloy is a heterogenous mixture.

  1. a, b

  2. c, d

  3. a, c

  4. b, d


Correct Option: B
Explanation:

Alloys have properties which can different from the constituent metals. In fact it is possible to make alloys having required properties.

Alloy is a homogeneous mixture. Steel is an alloy of iron and carbon.

Which of the following alloy contains mercury?

  1. Bronze

  2. Zinc amalgam

  3. Brass

  4. German silver


Correct Option: B
Explanation:

Amalgam is a substance formed by the reaction of mercury with another metal.Almost all metals form amalgams with mercury with exceptions being iron,platinum,tungsten and tantalum.Silver-mercury amalgams are important in dentistry.

Identify the alloy which does not contain zinc metal.

  1. Gun metal

  2. German silver

  3. Brass

  4. Bronze


Correct Option: D
Explanation:

Bronze is an alloy of $Cu$ and $Sn$. It does not contain zinc metal.

Alloy                                 Metals present
Gun metal $Cu$ (88%) $Sn$ (10%) $Zn$ (2%)
German silver $Cu,\ Zn$ and $Ni$
Brass $Cu$ and $Zn$
Bronze $Cu$ and $Sn$

Solder is an alloy of  ____________.

  1. $Cu+Zn$

  2. $Pb+Sn$

  3. $Pb+Sb$

  4. $Cu+Sn$


Correct Option: B
Explanation:

Solder is an alloy of Sn and Pb which makes alloy with high corrosion resistance.

Zinc metal is used in galvanization.

  1. True

  2. False


Correct Option: A
Explanation:

Galvanization or galvanizing is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are submerged in a bath of molten zinc.

An alloy is a _________ mixture of two or more metals, or a metal and a non-metal.
  1. Heterogeneous

  2. Homogeneous

  3. Both A and B

  4. None of these


Correct Option: B
Explanation:

An alloy is a homogenous mixture of two or more metals or non metals or nonmetals mixed in a molten state.

Find the odd one out.

  1. Constantan

  2. Manganin

  3. Nichrome

  4. Chromium


Correct Option: D
Explanation:

Only chromium is not an alloy.
Constantan is a copper–nickel alloy.
Manganin is an
alloy of  86% copper, 12% manganese, and 2% nickel.
Nichrome is an
alloy of nickel, chromium.

State whether true or false :

Cars are made from steel which is an alloy of carbon and aluminium.

  1. True

  2. False


Correct Option: B
Explanation:

The most common material used in building cars is Steel because it is strong, easy to work with, cheap, readily available and almost every car will have some steel in it. 


It can be used for parts like the roof, chassis, wheels, brakes, exhaust and engine. It doesn’t take extremely specialised tools or knowledge to produce, manufacture and repair steel so is the cheapest metal used in car building.


But steel is an alloy of iron and carbon and not aluminium and carbon.
Statement is false.

Option B is correct.

Metal present in gun metal are:

  1. $Cu,\ Zn,\ Ni$

  2. $Cu,\ Sn,$ and $Zn$

  3. $Cu,\ Sn$

  4. $Cu,\ Al$


Correct Option: B
Explanation:

101652

1) Cu, Sn and Zn.

2) Gunmetal, also known as red brass, is a type of bronze – an alloy of copper, tin, and zinc.

3) Gunmetal can also mean steel treated to simulate gunmetal bronze.

Steel is heated to the very high temperature and then plunged into cold water. This process is called _______.

  1. tempering

  2. anodising

  3. regulating

  4. anealing


Correct Option: A
Explanation:

Annealing is the process of heating the steel to high temperature to soften it and it undergoes three phases. Quenching involves heating the steel and tempering in water or oil. This rapid cooling results in hard and brittle steel.

An alloy is :

  1. an element

  2. a compound

  3. a homogeneous mixture

  4. a heterogeneous mixture


Correct Option: C
Explanation:

An alloy is a homogeneous mixture of two or more metals in a definite proportion. 


The alloy is made by mixing a metal in the molten state with another metal and then solidified.

Hence the correct option is C.

Identify the alloy containing a non- metal as a constituent in it.

  1. Bell metal

  2. Bronze

  3. Invar

  4. Steel


Correct Option: A

Spiegeleisen is an alloy of :

  1. $Cu+Zn+Ni$

  2. $Ni+Cr$

  3. $Mn+si+C$

  4. $Fe+Cr+Ni$


Correct Option: C
Explanation:

Spiegeleisen is a ferromanganese alloy.
It contains iron, manganese and carbon.
Manganese is present to about 15%.

An alloy of copper, silver and gold is found to have copper constituting the ccp lattice. If silver atoms occupy the edge wares and gold is resent at a body centre. the alloy has a formula?

  1. $ Cu _{4}Ag _{2}Au $

  2. $ Cu _{4}Ag _{4}Au $

  3. $ Cu _{4}Ag _{3}Au $

  4. CuAgAu


Correct Option: C

Which of the following is an alloy?

  1. Silver

  2. Gallium

  3. $22$ carat gold

  4. $24$ carat gold


Correct Option: C
Explanation:

22 karat gold contains 22 parts gold and 2 parts of other metals added as alloy. ... 18 karat gold contains 18 parts pure gold with 6 parts of other metals added. In the West the karat is expressed in fineness.

Hence 22 carat gold is an alloy.

Bell-metal is an alloy of

  1. Cu+Pb

  2. Cu+Sn

  3. Cu+Zn

  4. Cu+Ni


Correct Option: B
Explanation:

Bell metal is a hard alloy used for making bells and related instruments, such as cymbals. It is a form of bronze, usually approximately 4:1 ratio of copper to tin (e.g., 78% copper, 22% tin by mass).

Which of the following pairs of elements cannot form an alloy?

  1. $Zn,\ Cu$

  2. $Fe,\ Hg$

  3. $Fe,\ C$

  4. $Hg,\ Na$


Correct Option: B

Raney Nickel is finely divided nickel obtained by digesting alloys of $Ni/Al $ over $NaOH$.

  1. True

  2. False


Correct Option: A
Explanation:
Raney nickel is a fine-grained solid composed mostly of nickel derived from a nickel aluminum alloy
The alloy is treated with a concentrated solution of sodium hydroxide. The simplified leaching reaction is:
$2Al + 2NaOH + 6 H _2O \rightarrow  2 Na[Al{(OH)} _4] + 3 H _2$
After this process, leaching is done to form raney nickel which is powder and spongey.
Given statement is true.

Consider the following statements:
(a) Mass is not affected by temperature and pressure.
(b) Plasma contains ionised gases.
(c) Alloys are homogenous mixtures.
(d) Solution is a heterogeneous mixture.
Which of the above statements are correct?

  1. (a), (b) and (c)

  2. (b) and (c)

  3. (a), (c) and (d)

  4. (a) and (d)


Correct Option: A
Explanation:

a. An increasing or decreasing temperature doesn't affect mass. Mass is the amount of matter in an object whereas temperature is the human sense of kinetic energy of matter. Thermal energy is very, very, very small, so no, it is not measurable as mass.

b. Plasma is the fourth state of matter. Plasma is an ionized gas, a gas into which sufficient energy is provided to free electrons from atoms or molecules and to allow both species, ions and electrons, to coexist.

c. An alloy is a homogeneous mixture of 2 or more metals or metal with 2 or more semi-metals.

d. It is homogeneous because the additions take place in the liquid state, so the atoms mingle with each other and mix thoroughly.

An alloy is a material composed of two or more metals or a metal and a nonmetal. 

  1. True

  2. False


Correct Option: A
Explanation:

An alloy is a material composed of two or more metals or a metal and a nonmetal. An alloy may be a solid solution of the elements (a single phase), a mixture of metallic phases (two or more solutions) or an intermetallic compound with no distinct boundary between the phases. Solid solution alloys give a single solid phase microstructure, while partial solutions exhibit two or more phases that may or may not be homogeneous in distribution, depending on the thermal (heat treatment) history of the material. An inter-metallic compound has one other alloy or pure metal embedded within another pure metal.

The primary metal in an alloy is called:

  1. base

  2. metalloid

  3. crystal

  4. none of above


Correct Option: A
Explanation:

The term alloy is used to describe a mixture of atoms in which the primary constituent is a metal. The primary metal is called the base, the matrix, or the solvent.

Statement 1 : A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metal.
Statement 2 : The new bonds are weaker.

  1. Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1

  2. Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1

  3. Statement 1 is correct but Statement 2 is not correct

  4. Statement 1 is not correct but Statement 2 is  correct

  5. Both the Statement 1 and Statement 2 are not correct


Correct Option: A
Explanation:

Both Statement 1 and Statement 2 is correct and Statement 2 is the correct explanation of Statement 1.


A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metal because the new bonds are weaker.

Hence, the correct option is A.

Tinned iron sheets are used for making boxes for fruits, oils, vegetables etc.

  1. True

  2. False


Correct Option: A
Explanation:

Tinning is the process of thinly coating sheets of wroughtiron or steel with tin, and the resulting product is known as tinplate. While once more widely used, the primary use of tinplate now is the manufacture of tin cans. Formerly, tinplate was used for cheap pots, pans and other holloware. It has an extremely beautiful metallic luster as well as excellent properties in corrosion resistance, solderability, and weldability. 

So it's true.

Tin is used for making fusible alloys.

  1. True

  2. False


Correct Option: A
Explanation:

fusible alloy is a metal alloy capable of being easily fused, i.e. easily meltable, at relatively low temperatures. The most widely used fusible alloys contain high percentages of bismuth, combined with lead, tin, cadmium, indium and other metals. Bismuth has an impact on the melting point, as well as the growth and shrinkage characteristics of the alloys.

The main component of bronze is:

  1. cobalt

  2. copper

  3. tin

  4. aluminium


Correct Option: B
Explanation:

Bronze is an alloy consisting primarily of copper, commonly with about 12% tin and often with the addition of other metals (such as aluminium, manganese, nickel or zinc) and sometimes non-metals or metalloids such as arsenic, phosphorus or silicon.

$SiO _2$ (Silica) occurs in the form of:

  1. sand

  2. quartz

  3. opal

  4. all of these


Correct Option: D
Explanation:

Silica also known as silicon dioxide. It is found in nature as quartz, sand or opal. Silica more so than almost any material exists in many crystalline forms called polymorphs. Silica in the form of sand is used as ingredient in sand casting.

_________ cannot be readily separated by physical means.

  1. Mixtures

  2. Metals

  3. Alloys

  4. Non-metals


Correct Option: C
Explanation:

Alloys are metallic materials consisting of two or more elements combined in such a way that they cannot be readily separated by physical means. More than 90% of metals used are in the form of alloys.

Alloys are the examples of mixtures of:

  1. solid-in-gas

  2. gas-in-solid

  3. gas-in-gas

  4. solid-in-solid


Correct Option: D
Explanation:

An alloy is a mixture of two or more metals. Thusit is solid in solid.

The alloy bronze contains copper and tin. This is a:

  1. homogeneous mixture

  2. heterogeneous mixture

  3. solid solution of two immiscible metals

  4. pure substance


Correct Option: A
Explanation:

Bronze is an alloy consisting primarily of copper, commonly with about 12% tin and often with the addition of other metals (such as aluminium, manganese, nickel or zinc) and sometimes non-metals or metalloids such as arsenic, phosphorus or silicon.

All the alloys are homogeneous mixture.

Type metal is a well-known alloy made out of the three metals:

  1. $Pb,\ Sb, \ Sn$

  2. $Ni,\ Cu,\ Ag$

  3. $Ag,\ Ni,\ Zn$

  4. $Al, \ Cu, \ Zn$


Correct Option: A
Explanation:

Type metal is an alloy of lead, tin and antimony in different proportions depending on the application, be it individual character mechanical casting for hand setting, mechanical line casting or individual character mechanical typesetting and stereo plate casting.

Metallic bonding describes an array of positively charged metal cations surrounded by a sea of electrons that makes up a class of substances known as which of the following?

  1. Alloys

  2. Allotropes

  3. Isomers

  4. Ions


Correct Option: A
Explanation:

Answ: (A) Alloys

- We know that alloys is mixture of two or more metals. Which is held by metallic bond.
eg : brass which is made from copper and zinc.

An alloy is a specific type of substance that can best be described by which of the following?

  1. An alloy is a mixture of various metals that can also contain non-metal elements.

  2. An alloy is a compound made of different types of metals.

  3. An alloy can only contain metals from the transition elements.

  4. An alloy can only contain two pure metals mixed in even quantities.


Correct Option: A
Explanation:

Ans : (A) An alloy is a mixture of various metals that can also contain non-metals elements.

Eg : Steel is an alloy of iron (metal) and carbon (non-metal).

Statement 1: A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metals
Statement 2: The new bonds are weaker.

  1. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1

  2. Both the Statement 1 and Statement 2 are correct, but Statement 2 is not the correct explanation of Statement 1.

  3. Statement 1 is correct, but Statement 2 is not correct.

  4. Statement 1 is not correct, but Statement 2 is correct.


Correct Option: A
Explanation:

Both statement right and statement $2$ are correct Explanation.

Note : [alloy is the mixture of different metals .each metal having different size and structural arrangements. The different sizes of atoms in an alloy make their arrangement less regular than a pure metal. This makes the bonds between the atoms weaker and lower melting point.

Surface chemists design alloys for specific functions in everyday life.
Which of the following does not demonstrate a benefit of using an alloy?

  1. Gold is mixed with copper or silver to make a less expensive form that can be used in jewelry.

  2. Smaller atoms of one metal are incorporated into the structure of larger metal atoms to reduce malleability and improve strength of the structure.

  3. Densities of metals are closely matched to increase desirable properties without increased cost.

  4. The conductivity has been eliminated due to the stronger bonding of the different types of metals.


Correct Option: B
Explanation:

Ans: (B) Smaller atoms of one metal are incorporated into the structure of large metal atom to redue malleability and improve strength of structure.

Note : - Smaller atoms have greater ratios of surface area to volume which means greater ratio of atom boundary to dislocation.

Which substance would have the lowest melting point?

  1. ${ Mg } _{ 3 }{ Al } _{ 2 }$

  2. $Ca{ Cl } _{ 2 }$

  3. ${ Cu } _{ 2 }Sn$

  4. ${ C } _{ 12 }{ H } _{ 22 }{ O } _{ 11 }$


Correct Option: D
Explanation:

$C _{12}H _{22}O _{11} (Sucrose) -180^{\circ}C$

$Mg _{3}Al _{2}, CaCl _{2}$ and $Cu _{2}S _{n}$ show ionic bonding where as $C _{12}H _{22}O _{11}$ show covalent bonding. And we know melting point of covalent bonded compound is less then ionic compound.

Which of the following choices provides the BEST explanation for the fact that bronze, an alloy of copper and tin, is a good conductor of electricity?

  1. Copper and tin have similar atomic radii.

  2. Copper and tin have similar melting points.

  3. The structure contains a "sea" of mobile valence electrons.

  4. The structure consists of strong covalent bonds between the atoms.


Correct Option: C
Explanation:
Both tin and copper alloys having a free electron in their outermost valence shell. When potential energy is provided these electron move from one end to another and conduct the electricity.

An alloy of any metal with mercury is called amalgam and the electrical conductivity of an alloy is more than that of pure metals.

  1. True

  2. False


Correct Option: A
Explanation:

Alloys of mercury with metals like silver, copper, tin, zinc are used as amalgams.

Steel, composed of carbon and iron, is an example of an interstitial alloy.
Which of the following choices represents the best explanation for the fact that steel is harder and stronger than pure iron?

  1. Carbon atoms are more reactive with oxygen than iron atoms. This prevents the steel from forming rust.

  2. Carbon atoms are smaller than iron atoms. Carbon atoms fill the spaces between iron atoms, making the structure more rigid.

  3. Carbon atoms form strong bonds with other carbon atoms. This forms a protective layer on the surface of steel.

  4. Both carbon and iron are good conductors of electricity. This makes steel harder and stronger than pure iron.


Correct Option: B
Explanation:
Ans : (B) Carbon atoms are smaller than iron atoms. Carbon atoms fill the spaces between iron atom, making the structure $\%$ more rigid.
Note : - Steel is interstitial alloy of iron and carbon, due to smaller size of carbon, it easily fit between the metal atoms (iron) and provide Extra bonding to neighbouring atom, which makes alloy harder stronger (rigid).

When items of jewellery made of base metals like copper, iron or nickel are placed in a solution containing a compound of gold, a film of gold is deposited by:

  1. cooling to $5$ degree centigrade

  2. adding acid

  3. heating

  4. passing an electric current


Correct Option: D
Explanation:

Electroplating is the process in which a layer of a metal is deposited on metallic or non-metallic electrode by electrolysis in an electrolytic cell.

When items of jewellery made of base metals like copper, iron or nickel are placed in a solution containing a compound of gold, a film of gold is deposited by the process of electroplating which  requires passing an electric current in it.
Hence option D gives the correct answer.

Which of the following shows both the properties of both metals and non-metals?

  1. $\displaystyle F$

  2. $\displaystyle Li$

  3. $\displaystyle Fe$

  4. $\displaystyle He$

  5. $\displaystyle Si$


Correct Option: E
Explanation:

Silicon is a metalloid, a semimetallic element that is neither a metal nor a nonmetal but has some of the properties or characteristics of the two. A semi-metal in the periodic table, silicon is one of the elements that can't be found in nature in its elemental form. It is also one of the most common elements in nature, accounting for about 28 percent of the earth's crust by mass.

Monel metal is a metallic alloy of copper and nickel with $5$% iron. It is used in making:

  1. locks

  2. strong boxes

  3. almirahs

  4. motor parts


Correct Option: A
Explanation:

Monel is a group of nickel alloys, primarily composed of nickel (up to 67%) and copper, with small amounts of iron, manganese, carbon, and silicon. Stronger than pure nickel, Monel alloys are resistant to corrosion by many agents, including rapidly flowing seawater.

Being stronger than pure nickle Monel metal is used in making locks.
Hence option A is correct answer.

Which of the following is not an alloy containing tin metal?

  1. Solder for soldering electrical contacts

  2. Pewter for hardness

  3. Bronze for statues

  4. Brass for articles like bangles and utensils


Correct Option: D
Explanation:

 Brass for articles like bangles and utensils.

Brass is an alloy of copper and zinc having molecular formula ${Cu} _{3}{Zn} _{2}$

Which of the following is a steel that is resistant to acids?

  1. Nickel alloy steel

  2. Molybdenum steel

  3. Stainless steel

  4. Cobalt alloy steel


Correct Option: B
Explanation:

Molybdenum can be obtained from the minerals molybdenite, wulfenite and powellite. It is also obtained as a byproduct during tungsten and copper mining and processing. It has one of the highest melting points of all pure elements; however it is not resistant to acids.Hence, molybdenum steel is also not resistant to acids.

Hence option B is correct answer.

In metallurgy of iron, limestone provides flux for removing impurities as slag.

  1. True

  2. False


Correct Option: A
Explanation:

The above statement is true.
In agglomeration and separation of melted or smelted copper it is necessary to introduce iron oxide or limestone as flux to remove the impurities.

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