# Periodic Classification of Elements Online Test 10th Science Lesson 8 Questions in English

## Periodic Classification of Elements Online Test 10th Science Lesson 8 Questions in English

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 Question 1
How many elements were discovered by the scientists by 1860?
 A 100 B 5000 C 60 D 25
Question 1 Explanation:
By 1860, scientists had already discovered 60 elements and determined their atomic masses. They noticed that some elements had similar properties and hence arranged them into groups.
 Question 2
According to which property the elements were arranged in Mendeleev's periodic table? ##
 A Atomic mass B Number of protons C Valence Electrons D All the above
Question 2 Explanation:
Mendeleev’s periodic table had some discrepancies, which were difficult to overcome. For example the atomic mass of argon (39.95amu) is greater than that of potassium (39.10 amu) but argon comes before potassium in the periodic table.
 Question 3
Which of the fundamental property was not known to the earlier scientists?
 A Number of Protons B Number of Electrons C Number of Neutrons D Number of chemical reactions
Question 3 Explanation:
The fundamental property turned out to be the number of protons in an atom’s nucleus, something that could not have been known by Mendeleev and his contemporaries.
 Question 4
Who discovered the atomic number of the elements?
 A Antoine Lavoisier B Johns Berzelius C Robert Boyle D Henry Moseley
Question 4 Explanation:
Henry Moseley, a British scientist in 1912 discovered a new property of elements called atomic number, which provided a better basis for the periodic arrangement of the elements. It is a well-known fact that atomic number of an element is equal to the number of protons or the numbers of electrons present in the neutral atom of an element.
 Question 5
Which of these refers to the modified periodic law?
 A The Physical property depends on the source of the elements. B The Elements are classified based on the number of chemical reactions. C The Physical and chemical properties are the functions of the atomic numbers of the elements. D The Chemical property of an element is depends on the number of electrons.
Question 5 Explanation:
The periodic law was modified to frame a modern periodic law which states that “The physical and chemical properties of the elements are the periodic functions of their atomic numbers”.
 Question 6
Which of these statements is true regarding the modern periodic table?
 A The Elements are arranged in increasing order of atomic numbers. B The Elements are arranged in periods and groups C It highlights the regular repetition of properties of elements. D All the above
Question 6 Explanation:
With reference to the modern periodic law the elements were arranged in the increasing order of their atomic numbers to form the modern periodic table. The modern periodic table is a tabular arrangement of elements in periods and groups highlighting the regular repetition of properties of the elements.
 Question 7
How many periods are in the horizontal row of the periodic table?
 A 7 B 8 C 4 D 10
Question 7 Explanation:
The horizontal rows are called periods. There are seven periods in the periodic table.
 Question 8
How many elements are present in the first period of the periodic table?
 A 2 B 1 C 4 D 3
Question 8 Explanation:
First period (Atomic number 1 and 2): This is the shortest period. It contains only two elements (Hydrogen and Helium).
 Question 9
What is the last element in the second period of the periodic table?
 A Hydrogen B Lithium C Neon D Helium
Question 9 Explanation:
Second period (Atomic number 3 to 10): This is a short period. It contains eight elements (Lithium to Neon).
 Question 10
Which of this element is not present in the third period of the periodic table?
 A Aluminium B Lithium C Sulphur D Argon
Question 10 Explanation:
Third period (Atomic number 11 to 18): This is also a short period. It contains eight elements (Sodium to Argon).
 Question 11
Choose the Incorrect statements about the fourth period of elements.
1. The fourth group of elements consists of atomic values from 20 to 45.
2. The fourth group contains eighteen elements.
3. Ten transition elements are present in the fourth group.
 A i only B ii only C iii only D None of the above
Question 11 Explanation:
Fourth period (Atomic number 19 to 36): This is a long period. It contains eighteen elements (Potassium to Krypton). This includes 8 representative elements and 10 transition elements.
 Question 12
In which of this period the rubidium is classified in the periodic table?
 A Third B Second C Fifth D Fourth
Question 12 Explanation:
Fifth period (Atomic number 37 to 54): This is also a long period. It contains 18 elements (Rubidium to Xenon). This includes 8 representative elements and 10 transition elements.
 Question 13
How many Lanthanides are present in the sixth period of the modern periodic table?
 A 8 B 14 C 10 D 4
Question 13 Explanation:
Sixth period (Atomic number 55 to 86): This is the longest period. It contains 32 elements (Cesium to Radon). This includes 8 representative elements, 10 transition elements and 14 inner transition elements (Lanthanides).
 Question 14
How many new elements were added in the seventh period recently?
 A 4 B 10 C 3 D 7
Question 14 Explanation:
Seventh period (Atomic number 87 to 118): Like the sixth period this period also accommodates 32 elements. Recently 4 elements have been included by IUPAC.
 Question 15
How many groups of elements are classified in the periodic table?
 A 20 B 15 C 18 D 12
Question 15 Explanation:
The vertical columns in the periodic table starting from top to bottom are called groups. There are 18 groups in the periodic table.
 Question 16
Which of these are called as inner transition elements?
 A Lanthanides B Actinides C Group 3 D All the above
Question 16 Explanation:
The Lanthanides and Actinides which form part of Group 3 are called inner transition elements.
 Question 17
Which of this group does not have same number of valence electrons?
 A Group 18 B Group 7 C Group 8 D Group 10
Question 17 Explanation:
Except 'group 18', all the elements present in each group have the same number of electrons in their valence shell and thus have the same valency. For example, all the elements of group 1 have one electron in their valence shells (1s1). So, the valency of all the alkali metals is ‘1’.
 Question 18
Which of these given identical property results in similar chemical properties of elements?
 A Valance shell configurations B Atomic weight C Physical property D Number of protons
Question 18 Explanation:
As the elements present in a group have identical valence shell electronic configurations, they possess similar chemical properties.
 Question 19
Which of the given are the physical property of elements?
 A Melting point B Density C Boiling point D All the above
Question 19 Explanation:
The physical properties of the elements in a group such as melting point, boiling point and density vary gradually.
 Question 20
Which of these group elements are unreactive?
 A Group 1 B Group 20 C Group 18 D Group 12
Question 20 Explanation:
The atoms of the 'group 18' elements have stable electronic configuration in their valence shells and hence they are unreactive.
 Question 21
• Assertion (A): The physical and chemical properties are known by the electronic configuration of the elements.
• Reasoning(R): The electronic configuration of elements occurs repeatedly.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 21 Explanation:
The electronic configurations of elements help us to explain the periodic recurrence of physical and chemical properties.
 Question 22
Choose the correct statements.
1. Periodicity is the property of elements repeating at regular interval.
2. All the atomic properties of elements are periodic.
 A i only B ii only C Both i and ii D None of the above
Question 22 Explanation:
Anything which repeats itself after a regular interval is called periodic and this behavior is called periodicity. Some of the atomic properties of the elements are periodic.
 Question 23
Which of these are the periodic properties of the elements?
 A Ionic radius B Electron affinity C Ionization energy D All the above
Question 23 Explanation:
Properties such as atomic radius, ionic radius, ionization energy, electronegativity, electron affinity, show a regular periodicity and hence they are called periodic properties.
 Question 24
What is the value distance between center of nucleus and valence electron?
 A Atomic radius B Atomic number C Atomic distance D Atomic affinity
Question 24 Explanation:
Atomic radius of an atom is defined as the distance between the center of its nucleus and the outermost shell containing the valence electron.
 Question 25
• Assertion (A): Metal atoms atomic radius value is known as metallic radius.
• Reasoning(R): Metallic radius is measured as half the distance between the nuclei of adjacent atoms.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 25 Explanation:
Atomic radius in metal atoms is known as metallic radius. It is defined as half the distance between the nuclei of adjacent metal atoms.
 Question 26
Choose the correct statements.
1. Isolated atom radius can be easily measured.
2. Noble gas atomic radius is referred as covalent radius.
 A i only B ii only C Both i and ii D None of the above
Question 26 Explanation:
Direct measurement of the radius of an isolated atom is not possible. Except for noble gases, usually the atomic radius is referred to as covalent radius or metallic radius depending on the nature of the bonding between the concerned atoms.
 Question 27
What is the atomic radius value of non-metallic elements?
 A Covalent radius B Metallic radius C Non-metal radius D All the above
Question 27 Explanation:
In non-metallic elements, their atomic radius is known as covalent radius. It is defined as half the distance between the adjacent nuclei of two covalently bonded atoms of the same element in a molecule.
 Question 28
What is the change in atomic radius value in the groups from top to bottom?
 A Decreases B Constant C Increases D Similar value
Question 28 Explanation:
Along the period, from left to right the atomic radius of the elements decreases whereas along the groups, from the top to bottom, the atomic radius increases.
 Question 29
Which of this value is increased along the period?
 A Valence electron B Protons C Atomicity D All the above
Question 29 Explanation:
Along the period, the shell number remains the same but the number of protons (i.e. atomic number) increases.
 Question 30
Which of these results in atomic size reduction?
 A Positive charges B Shrinking of electron clouds C Strong attraction of electrons D All the above
Question 30 Explanation:
More and more positive charges impose a strong attraction over the electrons and thus the electron cloud shrinks towards the nucleus, which results in the decrease in the atomic size.
 Question 31
Choose the correct statements.
1. Ions are formed by lose or gain electrons in an atom.
2. A positively charged ion loses an electron.
3. Anion gains an electron and it is negatively charged ion.
 A i only B ii only C iii only D All the above
Question 31 Explanation:
Ions are formed when an atom loose or gain electrons. When a neutral atom loses an electron, it becomes a positively charged ion called cation. The gain of an electron by a neutral atom forms a negatively charged ion called anion.
 Question 32
Which of this property is used to determine the behavior and structure of ionic solids?
 A Atomicity B Size of ions C Chemical property of ions D None of the above
Question 32 Explanation:
The size of the ions is important to determine their behaviors in solutions and the structure of ionic solids.
 Question 33
Choose the correct statements.
1. Size of a cation may be smaller than the neutral atom.
2. Anion is always larger than the neutral atom.
 A i only B ii only C Both i and ii D None of the above
Question 33 Explanation:
The size of a cation is always smaller than its corresponding neutral atom. But the anion is larger than its neutral atom.
 Question 34
Which of these increases the size of anion?
 A Decrease in positive charge B Increase in negative charge C Decrease in positive charge D Increase in negative charge
Question 34 Explanation:
The positive charge increases the size of the cation decreases. The negative charge increases the size of the anion increases.
 Question 35
How many electrons are lost /gained by sodium to form its cation?
 A Gain single electron B Gain two electrons C Lose one electron D Lose four electrons
Question 35 Explanation:
Lithium and sodium lose the single electron from their outermost energy level to form cations. The ions so formed are smaller because the remaining electrons are at inner cells and attracted more strongly by the nucleus.
 Question 36
Which of this group number represents the carbon family of elements?
 A 15 B 2 C 14 D 17
 Question 37
What is the value of the minimum energy required to remove an electron from an isolated gaseous atom?
 A Ionization enthalpy B Ionization measure C Ionization force D Ionized value
Question 37 Explanation:
Ionization energy is the minimum energy required to remove an electron from an isolated gaseous atom in its ground state to form a cation. It is otherwise called ionization enthalpy.
 Question 38
What is the unit of ionization enthalpy?
 A kJ/mol B k mol C J D kJ
Question 38 Explanation:
Ionization enthalpy: It is measured in kJ/mol. Higher the ionization energy, it is more difficult to remove the electron.
 Question 39
How the ionization energy increases along a period of elements?
 A Decrease in atomic size B Increase in valence electron C Decrease in proton value D Increase in velocity of electrons
Question 39 Explanation:
As the atomic size decreases from left to right in a period, more energy is required to remove the electrons. So, the ionization energy increases along the period.
 Question 40
Choose the correct statements.
1. The atomic size increases down the group of elements.
2. Valence electrons are tightly bound down the group.
3.  Ionization energy increases down the group in a periodic table.
 A i only B ii only C iii only D All the above
Question 40 Explanation:
Down the group, the atomic size increases and hence the valence electrons are loosely bound. They require relatively less energy for the removal. Thus, ionization energy decreases down the group in the periodic table.
 Question 41
What is the value of amount of energy released from an isolated gas atom?
 A Electron affinity B Joule C Work D Enthalpy
Question 41 Explanation:
Electron affinity is the amount of energy released when an isolated gaseous atom gains an electron to form its anion. It is also measured in kJ/mol.
 Question 42
Choose the correct statements.
1. The Electron affinity decreases from left to right in a period of the periodic table.
2. The ionization energy value decreases from top to bottom of a group in the periodic table.
 A i only B ii only C Both i and ii D None of the above
Question 42 Explanation:
Like ionization energy, electron affinity also increases from left to right in a period and decreases from top to bottom in a group.
 Question 43
Which of these statements is true regarding the noble gas?
 A It has fewer acceptances of electrons. B The valence electrons are not present in the orbit. C Electrons cannot be added. D Has maximum electron affinity value.
Question 43 Explanation:
Noble gases show no tendency to accept electrons because the outer s and p orbitals of noble gases are completely filled. No more electrons can be added to them and hence their electron affinities are zero.
 Question 44
Which of these values does not depend on electronegativity?
 A Bond energy B Ionization potential C Electron affinity D Valence electrons
Question 44 Explanation:
Electronegativity is based on various experimental data such as bond energy, ionization potential, electron affinity, etc.
 Question 45
• Assertion (A): The Pauling scale is used to determine the electronegativity value.
• Reasoning(R): The nature of bonding of the atoms is predicted by the Pauling scale.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 45 Explanation:
Pauling scale is the widely used scale to determine the electronegativity, which in turn predicts the nature of bonding (ionic or covalent) between the atoms in a molecule.
 Question 46
• Match the electronegativity value of elements.
1. Bromine           i) 1
2. Sodium             ii) 2.8
3. Chlorine            iii) 4.0
4. Fluorine            iv) 3.0
 A iv, iii, i, ii B ii, i, iv, iii C iii, i, iv, ii D ii, i, iii, iv
Question 46 Explanation:
Electronegativity of some of the elements are given below F = 4.0, Cl = 3.0, Br = 2.8, I = 2.5, H = 2.1, Na = 1
 Question 47
What is the minimum electronegativity threshold value used to identify the character of elements?
 A 1 B 1.7 C 2.1 D 7
Question 47 Explanation:
If the difference in electronegativity between two elements is 1.7, the bond has 50% ionic character and 50% covalent character.
 Question 48
What is the character of an element if the electronegativity difference value is greater than 1.7?
 A Alkali B Compound C Ionic D Covalent
Question 48 Explanation:
Elements with electronegativity difference less than 1.7, the bond is considered to be more covalent and if the difference is greater than 1.7 the bond is considered to be more ionic.
 Question 49
Choose the Incorrect statements.
1. The value of electronegativity along the period is increases from left to right.
2.  The electrons attracts more strongly as the nuclear charge value decreases along the period.
 A i only B ii only C Both i and ii D None of the above
Question 49 Explanation:
Along the period, from left to right in the periodic table, the electronegativity increases because of the increase in the nuclear charge which in turn attracts the electrons more strongly.
 Question 50
Which of this value is decreased by the increasing number of valence shell?
 A Electronegativity B Atomicity C Radioactivity D Conductivity
Question 50 Explanation:
On moving down a group the electronegativity of the elements decreases because of the increased number of valence shells.
 Question 51
Which of the following metals is not found in a human body?
 A Sodium B Mercury C Potassium D Calcium
Question 51 Explanation:
We use metals in our day to day activities. It is the utmost need to have some metals like sodium, potassium, calcium, iron, etc. in the human body. Deficiency of these metals affects the metabolic activities thereby causing diseases
 Question 52
Which of these properties of metals are analyzed by the metallurgical process?
 A Physical properties B Atom structure C Metal extraction methods D All the above
Question 52 Explanation:
Metallurgy is a science of extracting metals from their ores and modifying the metals into alloys for various uses, based on their physical and chemical properties and their structural arrangement of atoms.
 Question 53
Which of these is not involved in the metallurgical process?
 A Separation of ore B Metal production C Classification of ore D Metal refining
Question 53 Explanation:
A metallurgical process involves three main steps as follows: Concentration or Separation of the ore: It is the process of removal of impurities from the ore. Production of the metal: It is the conversion of the ore into metal. Refining of the metal: It is the process of purification of the metal.
 Question 54
• Assertion (A): Ore is the mineral form of metal which can be economically extracted on a large scale.
• Reasoning(R): Minerals may be a single compound or a complex mixture of metals.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 54 Explanation:
Minerals: A mineral may be a single compound or a complex mixture of various compounds of metals found in the Earth. Ore: The mineral from which a metal can be readily and economically extracted on a large scale is said to be an ore.
 Question 55
Which is referred as the impurity in a metal ore?
 A Gangue (Matrix) B Alkali C Slug D Flux
Question 55 Explanation:
Gangue or Matrix: The rocky impurity associated with an ore is called gangue or matrix.
 Question 56
Which of these is used to remove the impurities in metal extraction process?
 A Steam B Pure ore C Flux D All the above
Question 56 Explanation:
Flux: It is the substance added to the ore to reduce the fusion temperature and to remove the impurities. E.g. Calcium oxide (basic), Silica (acidic). If the gangue is acidic, then basic flux is added and vice versa.
 Question 57
Which of this product is formed by the reaction of flux and gangue?
 A Slag B Ore C Pure metal D Solvents
Question 57 Explanation:
Slag: It is the fusible product formed when a flux reacts with a gangue during the extraction of metals. Flux + Gangue → Slag
 Question 58
Which is added to remove the impurities as slag in smelting process?
 A Flux B Positive charge C Valence electron D Heat
Question 58 Explanation:
Smelting is the process of reducing the roasted metallic oxide from the metal in its molten condition. In this process impurities are removed as slag by the addition of flux.
 Question 59
How many types of separation methods are categorized based on the nature of ore?
 A 5 B 3 C 7 D 4
Question 59 Explanation:
There are four major types of separation of ores based on the nature of the ore.
 Question 60
Choose the incorrect statements regarding the Hydraulic method?
 A Used for the heavier ores. B Based on the density difference principle. C Oxide ores use the hydraulic method. D Tinstone ore is separated by gravity separation method.
Question 60 Explanation:
Hydraulic (Gravity Separation) method Principle: The difference in the densities or specific gravities of the ore and the gangue is the main principle behind this method. Oxide ores are purified by this method. e.g. Hematite Fe2O3 the ore of iron. When the ore is heavier than the impurity, this method can be used.
 Question 61
Which of these ore is separated by the magnetic separation method?
 A Tinstone B Sulphides C Zinc blende D Haematite
Question 61 Explanation:
Magnetic separation method Principle: The magnetic properties of the ores form the basis of separation. When either the ore or the gangue is magnetic this method is employed. e.g., Tinstone SnO2 the ore of tin.
 Question 62
Which of these is not true regarding the froth floatation method?
 A Depends on the wettability of ore with oil. B The ore or the gangue is magnetic. C Used for lighter metals. D Sulphide ores are concentrated by this method.
Question 62 Explanation:
Froth floatation Principle: This process depends on the preferential wettability of the ore with oil (pine oil) and the gangue particles by water. Lighter ores such as Sulphide ores are concentrated by this method. e.g., Zinc blende (ZnS).
 Question 63
Which of this method is used for the pure form of ores?
 A Froth floatation method B Magnetic separation method C Leaching method D Gravity separation method
Question 63 Explanation:
Chemical method or Leaching method is employed when the ore is in a very pure form.
 Question 64
Identify the incorrect match.
1. Oxide Ore                   i) Cuprite
2. Sulphide Ore              ii) Iron pyrite
3. Carbonate Ore            iii) Galena
4. Halide Ore                    iv) Rock salt
 A i only B ii only C iii only D iv only
 Question 65
How many types of metal extraction is categorized from metal oxides?
 A 2 B 4 C 3 D 5
Question 65 Explanation:
Extraction of metal from metal oxide can be categorized into three types.
 Question 66
Match
1. Chromite              i) Madurai
2. Lime stone          ii) Tirunelveli
3. Tungsten              iii) Cuddalore
4. Gypsum                iv) Salem
5. Titanium               v) Tiruchirappalli
 A iv, iii, i, v, ii B iii, v, ii, iv, i C ii, iv, iii, i, v D iii, v, iv, ii, i
Question 66 Explanation:
Lime stone: Coimbatore, Cuddalore, and Dindugul Gypsum: Tiruchi and Coimbatore Districts Titanium minerals: Kanyakumari, Tirunelveli and Tuticorin. Chromite: Coimbatore and Salem district. Magnetite:. Dharmapuri, Erode, Salem, Thiruvannamalai. Tungsten: Madurai and Dindugal. (Reference: mineral resources of Tamil Nadu-ENVIS Centre, Tamil Nadu)
 Question 67
• Assertion (A): Metals possess a high lustre value.
• Reasoning(R): All metals are solids at room temperature.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 67 Explanation:
Physical properties Physical state: All metals are solids at room temperature except mercury and gallium. Lustre: Metals possess a high lustre (called metallic lustre).
 Question 68
Which of these metals have low density and hardness?
 A Potassium B Silver C Gallium D Zinc
Question 68 Explanation:
Hardness: Most of the metals are hard and strong (exceptions: sodium and potassium can be cut with a knife)
 Question 69
Which of these metals vaporize at high temperature?
 A Gallium B Tungsten C Sodium D Mercury
Question 69 Explanation:
Melting point and Boiling point: Usually metals possess high melting and boiling points and vaporize only at high temperatures (exceptions: gallium, mercury, sodium and potassium).
 Question 70
Which of these metals cannot be beaten into sheets?
 A Silver B Copper C Mercury D Tungsten
Question 70 Explanation:
Malleability: Metals are usually malleable they can be beaten into thin sheets without cracking (except zinc and mercury).
 Question 71
Which of this metal is not a good conductor?
 A Silver B Gold C Copper D Tungsten
Question 71 Explanation:
Conduction of heat and electricity: Metals are good conductors of heat and electricity; silver and copper excel in this property (exception: tungsten) Solubility: Usually, metals do not dissolve in liquid solvents.
 Question 72
Which of the following is not a chemical property?
 A Atomicity B Solubility C Valence electrons D Ions formation
Question 72 Explanation:
Chemical Properties Valence electrons: Atoms of metals usually have 1,2 or 3 electrons in their outermost shell. Formation of ions: Metals form Positive ions by the loss of electrons and hence they are electro positive. Discharge of ions: Metals are discharged at the cathode during the electrolysis of their compounds. Atomicity: Molecules of metals in their vapor state are usually monoatomic. Nature of oxides: Oxides of metals are usually basic.
 Question 73
Which of the statements are not true regarding aluminium?
 A Reactive metal. B It occurs in combined state. C Most abundant metal in earth's crust. D Non-reactive metal.
Question 73 Explanation:
Aluminium is the metal found most abundantly in the Earth’s crust. Since it is a reactive metal, it occurs in the combined state.
 Question 74
Which of these is not an ore of aluminium?
 A Bauxite B Cryolite C Zinc D Corundum
Question 74 Explanation:
The important ores of aluminium are as follows Ores of Aluminium Formula Bauxite Al2O3.2H2O Cryolite Na3AlF6 Corundum Al2O3
 Question 75
Which is the chief ore of aluminium?
 A Bauxite B Aluminate C Alumina D Graphite
Question 75 Explanation:
Bauxite is the chief ore of aluminium. The extraction of aluminium from bauxite involves two steps.
 Question 76
Which of this element is not involved in separation process of aluminium from bauxite?
 A Graphite B Caustic soda C Aluminium hydroxide D Sodium Meta aluminate
Question 76 Explanation:
The extraction of aluminium from bauxite involves the following steps: Bauxite ore is finely ground and heated under pressure with a solution of concentrated caustic soda solution at 150° C to obtain sodium meta aluminate. On diluting sodium meta aluminate with water, a precipitate of aluminium hydroxide is formed. The precipitate is filtered, washed, dried and ignited at 1000°C to get alumina. 2Al (OH)3 Al2O3 + 3H2O
 Question 77
Which of this reduction produces aluminium in Hall's process?
 A Oxygen B Electrolyte reduction C Electrochemical D Aqua reduction
Question 77 Explanation:
Electrolytic reduction of alumina –Hall’s Process Aluminium is produced by the electrolytic reduction of fused alumina (Al2O3) in the electrolytic cell.
 Question 78
Which of this element is not related to the Hall's process?
 A Graphite rods B Pure alumina C Steam D Fluorspar
Question 78 Explanation:
Cathode: Iron tank lined with graphite Anode: A bunch of graphite rods suspended in molten electrolyte. Electrolyte: Pure alumina+ molten cryolite + fluorspar (fluorspar lowers the fusion temperature of electrolyte)
 Question 79
What is the overall reaction of the Halls process?
1. 2 Al2O 3 → 4 Al +3 O2↑
2. Al + H2O → Al + H2
3. Al 2 + N 2 → 4 Al + NO2
4. Al2O4→ 4 Al +3 H2O↑
 A A B B C C D D
Question 79 Explanation:
Temperature: 900 - 950 °C Voltage used: 5-6 V Overall reaction: 2 Al2O3 → 4 Al +3 O2↑
 Question 80
Which of these combines with graphite to form CO2?
 A Hydrogen B Nitrogen C Oxygen D Carbon
Question 80 Explanation:
Aluminium is deposited at the cathode and oxygen gas is liberated at the anode. Oxygen combines with graphite to form CO2.
 Question 81
Which is not a physical property of aluminium?
 A Low density B Heat and Electricity conductor C Melting point is 100°C D White silvery metal
Question 81 Explanation:
Physical Properties of Aluminium It is a silvery white metal It has low density (2.7) and it is light It is malleable and ductile It is a good conductor of heat and electricity. Its melting point is 660 °C. It can be polished to produce a shiny attractive appearance.
 Question 82
Choose the correct statements.
1. Aluminium reacts with dry air and produces hydrogen.
2. Aluminium forms its oxide and nitride when heated at 800 °C
 A i only B ii only C Both i and ii D None of the above
Question 82 Explanation:
Reaction with air: It is not affected by dry air. On heating at 800 °C, aluminium burns very brightly forming it’s oxide and nitride. 4 Al + 3 O2 → 2 Al2O3 (Aluminium oxide) 2 Al + N2 → 2 AlN (Aluminium nitride)
 Question 83
• Assertion (A): Aluminium reacts with steam and produces hydrogen.
• Reasoning(R): Water does not react with aluminium because of the oxide layer.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 83 Explanation:
Reaction with water: Water does not react with aluminium due to the layer of oxide on it. When steam is passed over red hot aluminium, hydrogen is produced. 2 Al + 3 H2O → Al2O3 + 3 H2↑
 Question 84
Which of these reacts with aluminium and produces aluminates?
 A Acids B Alkalis C Base D Metals
Question 84 Explanation:
Reaction with alkalis: It reacts with strong caustic alkalis forming aluminates. 2 Al + 2 NaOH +2 H2O → 2 NaAlO2 + 3 H2↑ (Sodium meta aluminate)
 Question 85
Which of this gas is liberated by the reaction of aluminium with acids?
 A Hydrogen B Oxygen C Nitrogen D Carbon dioxide
Question 85 Explanation:
Reaction with acids: With dilute and con.HCl it liberates H2 gas. 2 Al + 6 HCl → 2 AlCl3 + 3 H2↑ (Aluminium chloride) Aluminium liberates hydrogen on reaction with dilute sulphuric acid and liberates sulphur dioxide on reaction with hot concentrated sulphuric acid.
 Question 86
Which of this acid reacts with aluminium and makes it as passive?
 A Hydrochloric acid B Nitric acid C Sulphuric acid D Carbonic acid
Question 86 Explanation:
Dilute or concentrated nitric acid does not attack aluminium but it renders aluminium passive due to the formation of an oxide film on its surface.
 Question 87
What is the result of the aluminothermic process?
 A Metal B Acid C Alkali D Oxygen
Question 87 Explanation:
As reducing agent: Aluminium is a powerful reducing agent. When a mixture of aluminium powder and iron oxide is ignited the latter is reduced to metal. This process is known as aluminothermic process. Fe2O3 + 2 Al → 2 Fe + Al2O3 + Heat.
 Question 88
Which is not a usage of Aluminium?
 A Electrical cables B Industrial machineries C Gold Jewelry D Household utensils
Question 88 Explanation:
Aluminium is used in household utensils, electrical cable industry, making aero planes and other industrial machine parts.
 Question 89
In which of this form copper is found naturally?
 A Native state only B Combined state only C Compounds only D Both a and b
Question 89 Explanation:
It was named as cuprum by the Romans because they got it from the Island of Cyprus. Copper is found in the native state as well as combined state.
 Question 90
Which of the following is not an ore of copper?
 A Cuprite B Ruby copper C Cu2O D CuSO4
Question 90 Explanation:
Ores of copper Formula Copper pyrites CuFeS2 Cuprite or ruby copper Cu2O Copper glance Cu2S
 Question 91
Which of this is the chief ore of copper?
 A Copper pyrite B Ruby copper C Copper glance D Cuprite
Question 91 Explanation:
The chief ore of copper is copper pyrite. It yields nearly 76% of the world production of copper.
 Question 92
How many steps are involved in the preparation of copper from its ore?
 A 4 B 3 C 5 D 7
Question 92 Explanation:
Concentration of ore: The ore is crushed and the concentrated by froth floatation process and Roasting, Smelting, Bessemerisation and Refining
 Question 93
In which part impure copper metal is used in copper production technique?
 A Cathode B Anode C Electrolyte D All the above
Question 93 Explanation:
Cathode: A thin plate of pure copper metal. Anode: A block of impure copper metal. Electrolyte: Copper sulphate solution acidified with Sulphuric acid. When electric current is passed through the electrolytic solution, pure copper gets deposited at the cathode and the impurities settle at the bottom of the anode in the form of sludge called anode mud.
 Question 94
Which of the following is not a quality of copper?
 A High melting point B High density C Low lustre D Brown metal
Question 94 Explanation:
Copper is a reddish brown metal with high lustre high density and high melting point (1356°C).
 Question 95
Which of these causes the copper to form its carbonates?
 A CO2 B Sulphur C Impurities D Steam
Question 95 Explanation:
Chemical Properties of Copper Action of Air and Moisture: Copper gets covered with a green layer of basic copper carbonate in the presence of CO2 and moisture. 2 Cu + O2 + CO2 + H2O → CuCO3.Cu(OH)2
 Question 96
Which of these are formed by reaction of heat and copper?
 A Oxide B Sulphide C Nitrite D Carbonate
Question 96 Explanation:
Action of Heat: On heating at different temperatures in the presence of oxygen, copper forms two types of oxides CuO and Cu2O. 2 Cu + O2 below 1370K 2 CuO (copper II oxide- black) 4 Cu + O2 above 1370K 2 Cu2O (copper I oxide – red)
 Question 97
• Assertion (A): Copper dissolves in dilute HCl and H2SO4 in the presence of air.
• Reasoning(R): Without air the dilute acids does not react with copper.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 97 Explanation:
With dilute HCl and dilute H2SO4: Dilute acids such as HCl and H2SO4 have no action on these metals in the absence of air. Copper dissolves in these acids in the presence of air. 2 Cu + 4 HCl + O2 (air) 2 CuCl2 + 2 H2O
 Question 98
Which of these following gas is liberated in the reaction of copper and HNO3?
 A Nitric oxide B Hydrogen Sulphide C Carbon monoxide D Helium
Question 98 Explanation:
With dil. HNO3: Copper reacts with dil. HNO3 with the liberation of Nitric Oxide gas. 3 Cu + 8 HNO3 → 3 Cu (NO3)2 + 2 NO ↑ + 4H2O
 Question 99
What is the end product of copper reacting with chlorine?
 A Copper nitrate B Copper Sulphide C Copper II chloride D Cupric acid
Question 99 Explanation:
Action of Chlorine: Chlorine reacts with copper resulting in the formation of copper (II) chloride. Cu + Cl2 CuCl2
 Question 100
Which of these does not affect the composition of copper?
 A Alkalis B Chlorine C Acids D Heat
Question 100 Explanation:
Action of Alkalis: Copper is not attacked by alkalis
 Question 101
What are the uses of copper?
 A Electroplating B Gold and silver jewels C Electric cables and appliances D All the above
Question 101 Explanation:
Uses of Copper: It is extensively used in manufacturing electric cables and other electric appliances. It is used for making utensils, containers, calorimeters and coins. It is used in electroplating. It is alloyed with gold and silver for making coins and jewels.
 Question 102
What are the natural forms of iron?
 A Oxides B Sulphides C Carbonates D All the above
Question 102 Explanation:
Iron is the second most abundant metal available next to aluminium. It occurs in nature as oxides, sulphides and carbonates.
 Question 103
Match
1. Iron pyrite       i) Fe2O3
2. Haematite       ii) Fe3O4
3. Magnetite        iii) FeS2
 A iii, i, ii B i, iii, ii C ii, iii, i D ii, i, iii
Question 103 Explanation:
The ores of iron are as follows: Ores of iron Formula Haematite Fe2O3 Magnetite Fe3O4 Iron pyrite FeS2
 Question 104
Which of these ore is the chief source of iron?
 A Haematite B Magnetite C Iron Pyrite D All the above
Question 104 Explanation:
Iron is chiefly extracted from haematite ore (Fe2O3)
 Question 105
Which of these is used in gravity separation to clean powdered ore?
 A Water steam B Low pressure air C High pressure air D Cold water
Question 105 Explanation:
Concentration by Gravity Separation: The powdered ore is washed with a steam of water. As a result, the lighter sand particles and other impurities are washed away and the heavier ore particles settle down.
 Question 106
Which of these iron impurities are oxidized in the roasting and calcination method?
 A Sulphur B Arsenic C Phosphorus D All the above
Question 106 Explanation:
Roasting and Calcination: The concentrated ore is strongly heated in a limited supply of air in a reverberator furnace. As a result, moisture is driven out and sulphur, arsenic and phosphorus impurities are oxidized off.
 Question 107
Which of the region is known as the fusion zone?
 A Middle region B Upper region C Lower region D All the above
Question 107 Explanation:
The Middle Region (Fusion Zone) – The temperature prevails at 1000°C. In this region, CO2 is reduced to CO. CO2 + C 2 CO – Heat Limestone decomposes to calcium oxide and CO2. CaCO3 CaO + CO2 – Heat These two reactions are endothermic due to absorption of heat. Calcium oxide combines with silica to form calcium silicate slag. CaO + SiO2 CaSiO3
 Question 108
Which of this iron is formed in the reduction zone?
 A Spongy iron B Pig iron C Cast iron D All the above
Question 108 Explanation:
The Upper Region (Reduction Zone)- The temperature prevails at 400°C . In this region carbon monoxide reduces ferric oxide to form a fairly pure spongy iron. Fe2O3 + 3CO 400°C 2Fe + 3CO2 ↑ The molten iron is collected at the bottom of the furnace after removing the slag. The iron thus formed is called pig iron. It is remelted and cast into different moulds. This iron is called cast iron.
 Question 109
Which of these physical properties of iron is not true?
 A A lustrous metal. B Low tensility and ductility. C Can be magnetized. D Greyish white color.
Question 109 Explanation:
Physical properties of Iron: It is a lustrous metal, greyish white in color. It has high tensility, malleability and ductility. It can be magnetized.
 Question 110
Which of these results in heating iron with air or oxygen?
 A Hydrated ferric sulphate B Ferric Sulphide C Ferrous oxide D Carbon monoxide
Question 110 Explanation:
Reaction with air or oxygen: Only on heating in air iron forms magnetic oxide. 3 Fe + 2 O2 Fe3O4 (black)
 Question 111
• Assertion (A): The Brown hydrated ferric oxide forming on the surface of iron is called as rust.
• Reasoning(R): Exposing iron to moist air forms rust and the phenomenon is known as rusting.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 111 Explanation:
Reaction with moist air: When iron is exposed to moist air, it forms a layer of brown hydrated ferric oxide on its surface. This compound is known as rust and the phenomenon of formation of rust is known as rusting. 4 Fe+ 3 O2 + x H2O 2 Fe2O3 . x H2O(rust)
 Question 112
Which of these results in magnetic oxide with iron?
 A Cool water B Hydrogen gas C Steam D High pressure water
Question 112 Explanation:
Reaction with steam: When steam is passed over red hot iron, magnetic oxide is formed. 3 Fe + 4 H2O (steam) Fe3O4 + 4 H2 ↑
 Question 113
What is the result of the chemical reaction of iron and chlorine?
 A Ferric Chloride B Ferrous oxides C Ferrous nitrates D None of the above
Question 113 Explanation:
Reaction with chlorine: Iron combines with chlorine to form ferric chloride. 2Fe + 3Cl2 2FeCl3 (ferric chloride)
 Question 114
Which of this gas is liberated in the chemical reaction of Iron and acids?
 A Carbon dioxide B Hydrogen C Nitrogen D Helium
Question 114 Explanation:
Reaction with acids: With dilute HCl and dilute H2SO4 it liberates H2 gas. Fe + 2HCl FeCl2 + H2 ↑ Fe + H2SO4 FeSO4 + H2 ↑
 Question 115
Which acid reacts with iron results in its nitrates?
 A HNO3 B H2SO4 C HCl D H2S
Question 115 Explanation:
With dilute HNO3 in cold condition iron gives ferrous nitrate and ammonium nitrate.
 Question 116
Which of these is not a usage of pig iron?
 A Pipes B Railings C Television towers D Drain pipes
Question 116 Explanation:
Pig iron (Iron with 2.0% - 4.5% of carbon): It is used in making pipes, stoves, radiators, railings, manhole covers and drain pipes.
 Question 117
• Assertion (A): Steel is used in the constructions, machineries and for transmission cables.
• Reasoning(R): Iron with 0.25%- 2.0% of carbon is used for steel.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 117 Explanation:
Steel (Iron with 0.25% - 2.0% of carbon): It is used in the construction of buildings, machinery, transmission cables and T.V towers and in making alloys.
 Question 118
What percentage of carbon makes a wrought iron?
 A < 0.50% B =0.25% C >0.15% D <0.25%
Question 118 Explanation:
Wrought iron (Iron with < 0.25% of carbon): It is used in making springs, anchors and electromagnets.
 Question 119
• Assertion (A): Alloy is a heterogeneous mixture of two or more metals.
• Reasoning(R): The alkali elements of metals are used to form an alloy.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 119 Explanation:
An alloy is a homogeneous mixture of two or more metals or of one or more metals with certain non-metallic elements.
 Question 120
Which of this metal is used to increase the strength and utility of gold?
 A Copper B Zinc C Silver D Brass
Question 120 Explanation:
The properties of alloys are often different from those of its components. Pure gold is brittle to be used. The addition of small percentage of copper enhances its strength and utility.
 Question 121
Which of these is used with metals in an amalgam?
 A Gold B Iron C Copper D Mercury
Question 121 Explanation:
An amalgam is an alloy of mercury with another metal. These alloys are formed through metallic bonding with the electrostatic force of attraction between the electrons and the positively charged metal ions. Silver tin amalgam is used for dental filling.
 Question 122
Which of these metals are used to make brass?
 A Zinc, Copper B Iron, Tin C Copper, Gold D Silver, Zinc
Question 122 Explanation:
Method of making alloys : By fusing the metals together. E.g. Brass is made by melting zinc and copper.
 Question 123
Which of these metals does not included in making wood metal?
 A Lead B Bismuth C Copper D Cadmium powder
Question 123 Explanation:
Method of making alloys: By compressing finely divided metals. E.g. Wood metal: an alloy of lead, tin, bismuth and cadmium powder is a fusible alloy.
 Question 124
Which of these is used as solvent in solid alloy solutions?
 A High concentration metals B High density metals C Low concentration metals D Low density metals
Question 124 Explanation:
Alloys as solid solutions: Alloys can be considered as solid solutions in which the metal with high concentration is solvent and other metals are solute. For example, brass is a solid solution of zinc (solute) in copper (solvent).
 Question 125
Choose the correct statements.
1. Iron alloys can be classified into ferrous and Non-ferrous alloys.
2. Ferrous alloys contain iron as major component.
3. Aluminum alloy is an example of Non-ferrous alloys.
 A i only B ii only C iii only D All the above
Question 125 Explanation:
Based on the presence of Iron alloys can be classified into Ferrous alloys: Contain Iron as a major component. A few examples of ferrous alloys are Stainless Steel, Nickel Steel etc. Non-ferrous alloys: These alloys do not contain Iron as a major component. For example, Aluminium alloy, Copper alloy etc.
 Question 126
What type of alloy is Brass?
 A Copper Alloy B Ferrous Alloy C Aluminium Alloy D Iron Alloy
 Question 127
Which of these alloys are used in aircrafts and scientific instruments?
 A Magnalium B Bronze C Tin D Nickel steel
Question 127 Explanation:
Aluminium Alloys (Non- ferrous)
 Question 128
Which of these constitute the nickel steel?
 A Iron B Carbon C Nickel D All the above
Question 128 Explanation:
Iron Alloys (Ferrous)
 Question 129
Which of these is not the reason for alloying?
 A Modify appearance and color. B Lower melting point. C Increase hardness and tensile strength. D Decreases resistance to electricity.
Question 129 Explanation:
Reasons for alloying: To modify appearance and color, To modify chemical activity, To lower the melting point, To increase hardness and tensile strength, To increase resistance to electricity.
 Question 130
• Assertion (A): Alloying is destruction of materials by electrochemical and chemical reaction with environment.
• Reasoning(R): The natural process of alloying converts metals into its oxides, hydroxide or Sulphide.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 130 Explanation:
Alloying is the gradual destruction of metals by chemical or electrochemical reaction with the environment. It is a natural process which converts a metal into its oxide, hydroxide or Sulphide so that it loses its metallic characteristics.
 Question 131
Which of these are chemically known as rust?
 A Hydrated Ferric oxide B Ferrous oxide C Fe2O3.H2O D Both a and c
Question 131 Explanation:
Rust is chemically known as hydrated ferric oxide (it is formulated as Fe2O3 .xH2O).Rusting results in the formation of scaling reddish brown hydrated ferric oxide on the surface of iron and iron containing materials.
 Question 132
Which of these does not cause dry corrosion?
1. O2
2. H2O
3. H2S
4. N2
 A A B B C C D D
Question 132 Explanation:
Dry Corrosion or Chemical Corrosion: The corrosive action in the absence of moisture is called dry corrosion. It is the process of a chemical attack on a metal by a corrosive liquids or gases such as O2, N2, SO2, H2S etc. It occurs at high temperature. Of all the gases mentioned above O2 is the most reactive gas to impart the chemical attack.
 Question 133
• Assertion (A): Wet corrosion occurs due to the presence of moisture in metals.
• Reasoning(R): The electrochemical reaction of metal with water or aqueous solution of salt, acids and bases.
 A Both A and R is True and R is the correct explanation of A. B Both A and R is True but R is not the correct explanation of A. C A is True but R is False. D Both A and R is False.
Question 133 Explanation:
Wet Corrosion or Electrochemical Corrosion: The corrosive action in the presence of moisture is called wet corrosion. It occurs as a result of electrochemical reaction of metal with water or aqueous solution of salt or acids or bases.
 Question 134
Which of this metal uses alloying method to prevent from corrosion?
 A Stainless steel B Iron C Copper D Sodium
Question 134 Explanation:
Methods of preventing corrosion Alloying: The metals can be alloyed to prevent from the process of corrosion. E.g: Stainless Steel
 Question 135
Which is not a surface coating method for protecting metals?
 A Galvanization B Alloying C Anodizing D Electroplating
Question 135 Explanation:
Surface Coating: It involves application of a protective coating over the metal. It is of the following types: Galvanization, Electroplating, and Anodizing and Cathodic protection.
 Question 136
Which of these is used in galvanization method?
 A Zinc on iron sheets B Tin on iron rods C Copper on Gold D Electro chemical coating
Question 136 Explanation:
Galvanization: It is the process of coating zinc on iron sheets by using electric current.
 Question 137
Which of this process uses electric current to coat a metal?
 A Alloying B Anodizing C Cathodic protection D Electroplating
Question 137 Explanation:
Electroplating: It is a method of coating one metal over another metal by passing electric current.
 Question 138
Which of this metal is used for anodizing process?
 A Zinc B Tin C Aluminium D Copper
Question 138 Explanation:
Anodizing: It is an electrochemical process that converts the metal surface into a decorative, durable and corrosion resistant. Aluminium is widely used for anodizing process.
 Question 139
What metal is used for cathodic protection?
 A Sacrificial metal B Non-metals C Alloys D Alkalis
Question 139 Explanation:
Cathodic Protection: It is the method of controlling corrosion of a metal surface protected is coated with the metal which is easily corrodible. The easily corrodible metal is called sacrificial metal to act as anode ensuring cathodic protection.
 Question 140
When Pamban Bridge was opened in India?
 A 1930 B 1945 C 1914 D 1887
Question 140 Explanation:
Pamban is a railway bridge which connects the town of Rameshwaram on Pamban Island to mainland India. Opened on 1914, it was India’s first sea bridge in India until the opening of the Bandra Worli Sea Link in 2010.
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