Here we have mentioned most frequently asked Chemistry Interview Questions and Answers specially for freshers and experienced.
1. The nucleus of an atom consists of
A.electrons and neutrons
B.electrons and protons
C.protons and neutrons
D.All of the above
Ans:
C.protons and neutrons
2. The number of moles of solute present in 1 kg of a solvent is called its
A.molality
B.molarity
C.normality
D.formality
Ans:
A.molality
3. The most electronegative element among the following is
A.sodium
B.bromine
C.fluorine
D.oxygen
Ans:
C.fluorine
4. The metal used to recover copper from a solution of copper sulphate is
A.Na
B.Ag
C.Hg
D.Fe
Ans:
D.Fe
5. The number of d-electrons in Fe2+ (Z = 26) is not equal to that of
A.p-electrons in Ne(Z = 10)
B.s-electrons in Mg(Z = 12)
C.d-electrons in Fe(Z = 26)
D.p-electrons in CI(Z = 17)
Ans:
D.p-electrons in CI(Z = 17)
6. The metallurgical process in which a metal is obtained in a fused state is called
A.smelting
B.roasting
C.calcinations
D.froth floatation
Ans:
A.smelting
7. The molecules of which gas have highest speed?
A.H2 at -73oC
B.CH4 at 300 K
C.N2 at 1,027oC
D.O2 at 0oC
Ans:
A.H2 at -73oC
8. The oldest rocks in the earth’s crust were once molten, and came from deep inside the earth. The molten rock, called magma, spewed out in volcanic eruptions during the earth;s early life and solidified into hard rock’s called
A.granite
B.basalt
C.igneous rocks
D.sedimentary rocks
Ans:
C.igneous rocks
9. The law which states that the amount of gas dissolved in a liquid is proportional to its partial pressure is
A.Dalton’s law
B.Gay Lussac’s law
C.Henry’s law
D.Raoult’s law
Ans:
C.Henry’s law
10. The main buffer system of the human blood is
A.H2CO3 – HCO3
B.H2CO3 – CO32-
C.CH3COOH – CH3COO-
D.NH2CONH2 – NH2CONH+
Ans:
A.H2CO3 – HCO3
11. The gas present in the stratosphere which filters out some of the sun’s ultraviolet light and provides an effective shield against radiation damage to living things is
A.helium
B.ozone
C.oxygen
D.methane
Ans:
B.ozone
12. The names of the scientists, Newlands, Mendeleev, and Meyer are associated with the development of
A.atomic structure
B.metallurgy
C.periodic table of contents
D.discovery of elements
Ans:
C.periodic table of contents
13. The nucleus of a hydrogen atom consists of
A.1 proton only
B.1 proton + 2 neutron
C.1 neutron only
D.1 electron only
Ans:
A.1 proton only
14. The heat required to raise the temperature of body by 1 K is called
A.specific heat
B.thermal capacity
C.water equivalent
D.None of the above
Ans:
B.thermal capacity
15. The nuclear particles which are assumed to hold the nucleons together are
A.electrons
B.positrons
C.neutrons
D.mesons
Ans:
D.mesons
16. The mass of P4O10 that will be obtained from the reaction of 1.33 gram of P4 and 5.07 of oxygen is
A.2.05 gram
B.3.05 gram
C.4.05 gram
D.5.05 gram
Ans:
B.3.05 gram
17. The octane number of zero is assigned to
A.2-methyl octane
B.n-heptane
C.iso-octane
D.3-methyl octane
Ans:
B.n-heptane
18. The metal that is used as a catalyst in the hydrogenation of oils is
A.Ni
B.Pb
C.Cu
D.Pt
Ans:
A.Ni
19. The most abundant rare gas in the atmosphere is
A.He
B.Ne
C.Ar
D.Xe
Ans:
C.Ar
20. The Latin word formica means ant. The name formic acid is derived from this Latin word because
A.this acid, in ancient times, was used to eliminate ant-hills
B.this corrosive acid is secreted by ants to drive away their enemies
C.this acid was first obtained by the distillation of ants
D.ants are attracted by the odour of this acid
Ans:
C.this acid was first obtained by the distillation of ants
21. The ore which is found in abundance in India is
A.monazite
B.fluorspar
C.bauxite
D.magnetite
Ans:
A.monazite
22. The inherited traits of an organism are controlled by
A.RNA molecules
B.nucleotides
C.DNA molecules
D.enzymes
Ans:
C.DNA molecules
23. The heat energy produced when the human body metabolises 1 gram of fat is
A.30 KJ
B.1 KJ
C.39 KJ
D.29 KJ
Ans:
C.39 KJ
24. What are the number of moles of CO2 which contains 16 g of oxygen?
A.0.5 mole
B.0.2 mole
C.0.4 mole
D.0.25 mole
Ans:
A.0.5 mole
25. The main use of salt in the diet is to
A.make the taste of food better
B.produce in small amounts the hydrochloric acid required for the digestion of food
C.ease the process of cooking
D.increase the solubility of food particles in water
Ans:
B.produce in small amounts the hydrochloric acid required for the digestion of food
26. The monomer of polythene is
A.vinyl chloride
B.ethylene
C.ethyl alcohol
D.None of the above
Ans:
B.ethylene
27. The luster of a metal is due to
A.its high density
B.its high polishing
C.its chemical inertness
D.presence of free electrons
Ans:
D.presence of free electrons
28. The number of water molecules present in a drop of water (volume 0.0018 ml) at room temperature is
A.1.568 x 103
B.6.023 x 1019
C.4.84 x 1017
D.6.023 x 1023
Ans:
B.6.023 x 1019
29. The most malleable metal is
A.platinum
B.silver
C.iron
D.gold
Ans:
D.gold
30. The oil used in the froth floatation process is
A.coconut oil
B.olive oil
C.kerosene oil
D.pine oil
Ans:
D.pine oil
31. The number of waves in n x 10th Bohr’s orbit are
A.n2
B.n
C.n-2
D.n3
Ans:
B.n
32. The mass of one Avogadro number of helium atom is
A.1.00 gram
B.4.00 gram
C.8.00 gram
D.4 x 6.02 x 1023 gram
Ans:
B.4.00 gram
33. The items amenable to detection by soft x-rays are
A.contrabands
B.lead in bullets
C.narcotics
D.genuine coins from counterfeit coins
Ans:
D.genuine coins from counterfeit coins
34. The material which can be deformed permanently by heat and pressure is called a
A.thermoplastic
B.thermoset
C.chemical compound
D.polymer
Ans:
B.thermoset
35. The mass number of a nucleus is
A.always less than its atomic number
B.the sum of the number of protons and neutrons present in the nucleus
C.always more than the atomic weight
D.a fraction
Ans:
B.the sum of the number of protons and neutrons present in the nucleus
36. The inexpensive and commonly used variety of glass is called soda glass. It is called so because
A.was used initially for making bottles of soda(carbonated drink)
B.is made using soda(sodium carbonate)
C.was initially used for storing sodium carbonate
D.is made using soda lime
Ans:
B.is made using soda(sodium carbonate)
37. The gas used in the manufacture of vanaspati from vegetable oil is
A.hydrogen
B.oxygen
C.nitrogen
D.carbon dioxide
Ans:
A.hydrogen
38. The ionic radii of N3-, O2-, F- and Na+ follows the order
A.N3- > O2- > F- > Na+
B.N3- > Na+ > O2- > F-
C.Na+ > O2- > N3- > F-
D.O2- > F- > Na+ > N3-
Ans:
A.N3- > O2- > F- > Na+
39. The graphite rods in the nuclear reactor
A.react with U to release energy
B.produce neutrons
C.undergo combustion which triggers the nuclear fission
D.convert fast moving neutrons into thermal neutrons
Ans:
D.convert fast moving neutrons into thermal neutrons
40. The first metal used by man was
A.iron
B.copper
C.gold
D.bronze
Ans:
B.copper
41. The hydronium ion is
A.H+
B.HO –
C.H2+
D.H3O+
Ans:
D.H3O+
42. The most electropositive elements among the following is
A.Na
B.Ca
C.K
D.Cs
Ans:
D.Cs
43. The method that cannot be used for removing permanent hardness of water is
A.adding sodium carbonate
B.distillation
C.adding caustic soda
D.boiling
Ans:
D.boiling
44. The following are the half lives of four active isotopes. Which one of the following is the most dangerous to handle?
A.3 billion years
B.100 years
C.0.01 minute
D.13 days
Ans:
C.0.01 minute
45. The gas used for artificial ripening of green fruit is
A.ethylene
B.ethane
C.carbon dioxide
D.acetylene
Ans:
A.ethylene
46. Zone refining is used for the purification of
A.Au
B.Ge
C.Ag
D.Cu
Ans:
B.Ge
47. The main chemical constituent of the oil of cardamom which is responsible for flavour of this oil is
A.cineole
B.engenol
C.geraniol
D.limonene
Ans:
A.cineole
48. The molecule which has the highest percentage of ionic character among the following is
A.HI
B.HF
C.HCI
D.HBr
Ans:
B.HF
49. The high reactivity of fluorine is due to
A.its high electro negativity
B.small size of fluorine atom
C.availability of d-orbitals
D.strong F – F bond
Ans:
A.its high electro negativity
50. The iron ore magnetite consists of
A.Fe2O3
B.Fe3OH4
C.FeCO3
D.3Fe2O3 .. 3H2O
Ans:
A.Fe2O3
51. The ionisation energy of hydrogen atom in the ground state is x KJ. The energy required for an electron to jump from 2nd orbit to 3rd orbit is
A.5x/36
B.5x
C.7.2 x
D.x/6
Ans:
A.5x/36
52. The major constituent of air is
A.nitrogen
B.carbon dioxide
C.oxygen
D.hydrogen
Ans:
A.nitrogen
53. The main chemical constituent of clay is
A.silicon oxide
B.aluminium borosilicate
C.zeolites
D.aluminium silicate
Ans:
D.aluminium silicate
54. The mineral containing both magnesium and calcium is
A.magnesite
B.calcite
C.carnallite
D.dolomite
Ans:
D.dolomite
55. The metal does not give H2 on treatment with dilute HCL is
A.Zn
B.Fe
C.Ag
D.Ca
Ans:
C.Ag
56. The number of g-molecule of oxygen in 6.02 x 1024CO molecules is
A.1 gram of molecule
B.0.5 gram of molecule
C.5 gram of molecule
D.10 gram of molecule
Ans:
C.5 gram of molecule
57. The most extensive, commercially useful source of thorium as monazite sand occurs in India at
A.Orissa coast
B.Travancore coast
C.West Bengal coast
D.Gujarat coast
Ans:
B.Travancore coast
58. The main active constituent of tea and coffee is
A.nicotine
B.chlorophyll
C.caffeine
D.aspirin
Ans:
C.caffeine
59. The maximum number of isomers for an alkene with molecular formula C4H8 is
A.5
B.4
C.2
D.3
Ans:
B.4
60. The hardest form of carbon is
A.coke
B.graphite
C.diamond
D.charcoal
Ans:
C.diamond
61. The most important ore of aluminium is
A.bauxite
B.magnetite
C.haematite
D.monazite
Ans:
A.bauxite
62. The organic reaction represented by equation CH3 – CH = O + H2NOH gives CH3 – CH – NH + H2O is an example of
A.an addition reaction
B.a condensation reaction
C.an oxidation reaction
D.an elimination reaction
Ans:
B.a condensation reaction
63. The number of electrons presents in H+ is
A.zero
B.one
C.two
D.three
Ans:
A.zero
64. The hottest part of the gas flame is known as
A.luminous zone
B.dark zone
C.blue zone
D.non-luminous zone
Ans:
D.non-luminous zone
65. The human body is made up of several chemical elements; the element present in the highest proportion (65%) in the body is
A.carbon
B.hydrogen
C.oxygen
D.nitrogen
Ans:
C.oxygen
66. The isomerism which exists between CH3CHCI2 and CH2CI. CH2CI is
A.chain isomerism
B.functional group isomerism
C.positional isomerism
D.metamerism
Ans:
C.positional isomerism
67. The half life period of an isotope is 2 hours. After 6 hours what fraction of the initial quantity of the isotope will be left behind?
A.1/6
B.1/3
C.1/8
D.1/4
Ans:
C.1/8
68. The number of waves made by an electron moving in an orbit having maximum magnetic quantum number is +3
A.4
B.5
C.2
D.zero
Ans:
A.4
69. The number of atoms present in 21.6 gram of silver (atomic weight = 108) are same as the molecules in
A.1.8 gram of H2O
B.12 moles of KMnO4
C.0.6N H2SO4
D.4.6 gram of C2H5OH
Ans:
B.12 moles of KMnO4
70. The National Chemical Laboratory is situated in
A.New Delhi
B.Bangalore
C.Pune
D.Patna
Ans:
C.Pune
71. Explain the term Aliquot and Diluent?
Ans:
Aliquot : It is a measured sub-volume of original sample
Diluent: Material with which sample is diluted
72. Explain what is molality?
Ans:
Molality is the number of solute that is present in 1 kg of a solvent.
73. Explain what is titration?
Ans:
Titration is a process to determine the molarity of a base or an acid. In this process a reaction is carried out between the known volumes of a solution with a known concentration, against the known volume of a solution with an unknown concentration.
74. Explain what is buffer?
Ans:
A buffer is an aqueous solution which has highly stable pH. It is a blend of a weak acid and its conjugate base or vice versa. On adding small amount of base or acid to buffer, its pH hardly changes.
75. Explain how buffer works?
Ans:
In buffer when hydrogen ion is added, it will neutralized by the base in buffer. Hydroxide ion will be neutralized by the acid. On the overall pH of the buffer solution, these neutralization reactions will not show much effect.
While when you select an acid as a buffer solution, try to use an acid acid that has a pH closed to your desired pH. This will help your buffer to achieve nearly equivalent amount of acid and conjugate base, so that it will enable to neutralize as much as H+ and OH -.
76. Explain what is mole?
Ans:
Mole is the unit used to define the number of chemical substance present in a substance. It is the amount of substance which consists of the same number of chemical units as there are atoms in exactly 12 gram of pure carbon-12.
77. How will you calculate how many moles of glucose present in 320 mL of 5.0 M of glucose solution?
Ans:
First step: Convert the volume from millilitres to litres
320 X (1 litre/1000mL) = 0.320 L solution
Second use the formula = M x V
= 5.0 moles glucose/ litre solution X 0.320 L solution
= 1.6 moles of glucose present in 320mL of solution
78. Explain what is the difference between fractionation and distillation?
Ans:
Both methods are used to separate the components present in the solution based on the melting points
Distillation : This technique is used when boiling point of chemicals are different in the mixtures
Fractionation : This technique is used when boiling point of chemicals are close to each other in the mixtures
79. Mention the formula to calculate pH of a solution?
Ans:
In order to calculate the pH of a solution you have to use the formula pH= -log [H+] or pH = -log [H3O+]
80. Explain what is the difference between Molarity and Normality?
Ans:
Both techniques are used to the amount of chemical present in the solution. However they are almost similar but differs in
                      Molarity |                       Normality |
–      Molarity is used to know the total amount of molecules in a 1 litre solution | –      Normality is used to know the total number of reactive units in 1 litre of solution |
–      It is expressed as moles of a compound per litre of solution | –      It is expressed in equivalent per litre |
81. Explain what is Valency?
Ans:
A valency is a property of a groups or atoms, equal to the number of atoms of hydrogen that the group or atom could combine with or displace it in forming compounds.
82. Define what is Avogadro’s law?
Ans:
According to Avogadro’s law, at same temperature and pressure equal volume of gases contains the same number or molecules regardless of the chemical nature and physical properties.
Avogadro’s number = 6.023 X 10 (-23)
83. Explain what makes a molecule into organic molecule?
Ans:
In a molecule when hydrogen atom is less than the ratio of carbon atom, then such molecules are referred as an organic molecule.
84. Explain what is the metal used to extract copper from the solution of copper sulphate?
Ans:
Fe or ferrous is the metal that is used to extract copper from the solution of copper sulphate.
85. Explain what is the chemical composition of fat in human body?
Ans:
Fat found in human body is mainly composed of
Glycerides
Glycerides+Phospholipids
Glycolipids
Phosphoinotisides
Tocopherol
86. What is the monomer of polyethene?
Ans:
The monomer of polyethene is ethylene
87. Explain what is the formula you will use to calculate how many millilitres of 5.5 M NaOH are required to prepare 400 mL of 1.5M NaOH?
Ans:
To know the amount or volume of NaOH to prepare 400 mL of 1.5 M NaOH, we use formula
M1 X V1 = M2 X V2
V1 = M2 X V2/ M1
But before that we will convert 400 mL into litre = 0.4 L
5.5 X V1 = 1.5 M x 0.4 L
V1 = 1.5 M X 0.4L/ 5.5
V1= 0.10 L
V1 = 100mL
So, you need 100mL of 5.5 NaOH
88. Explain why graphite rod is used in nuclear reactor?
Ans:
Graphite rod is used in nuclear reactor to convert fast moving neutrons into thermal neutrons.
89. Mention how many millilitre is equal to 1 litre and how many microliter is equal to litre?
Ans:
1 millilitre = 0.0001 litre
1 microliter = 0.0000001 litre
90. Define what is oxidation and reduction reaction?
Ans:
Oxidation = When there is a loss of hydrogen or electrons, OR gain of oxygen is known as Oxidation reaction.
Reduction = When there is a gain of hydrogen or electron OR loss of oxygen is known as reduction reaction
Example of oxidation-reduction reaction is observed in human body, when an electron is transferred into the cell and oxidation of glucose take place from which we get the energy.
91. Trimethylamine Is A Pyramidal Molecule. What Is The Hybridization At Nitrogen?
Ans:
The nitrogen is bonded to three CH3 groups and has a lone pair, so the hybridisation is sp3.
92. How Many Stereoisomers Of Phenylpropylene Oxide Are There?
Ans:
Two positional isomer A and B & two Stereoisomer of each so, total 4 isomers.
93. Which One Of The Following Is Not Aromatic? 1)cyclotetrane 2)benzene 3)napthalene 4)anthracene ?
Ans:
cyclotetrane, because of the double bonds are not conjugation
94. Number Of Sigma Bonds Present In Benzene Are Same As ..?
Ans:
Number of Sigma bonds present in Benzene are same as Borazine (inorganic Benzene).
no. of sigma bonds in Benzene= 12 (C6H6)
no. of sigma bonds in Borazine= 12 (B3N3H6)
95. The Name Benzene Was Proposed By?
Ans:
Kekule
96. Which Is Useful In The Manufacture Of Insectisides?
Ans:
Rotenone, Azadirachtin are natural insecticides, synthetic routes are deveoped recently.
DDT, Gammaxene were used but were scraped out as they pose health hazards and are insects are able sustain the max. dosages every year. Generally, Semio-chemicals, a class of compounds found in insects themselves are being studied and used as effective insecticides and warfare agents.
97. What Are The 4 Classes Of Unsaturated Fatty Acids?
Ans:
Monounsaturated fat: This is a type of fat found in a variety of foods and oils.
Polyunsaturated fat: This is a type of fat found in plant-based foods and oils.They can be divided into two groups known as omega-3 fats and omega-6 fats.
Omega-3 fatty acids: One type of polyunsaturated fat made up of mainly omega-3 fatty acids and may be beneficial to heart.
Omega-6 fats decrease risk of heart disease when they are consumed in place of saturated and trans fats.
98. What Is The Difference Between Coordinate Covalent Bond And Covalent Bond?
Ans:
IN coordinate covalent bond electrons which are shared by both the atoms are comtributed by only one atom . This is otherwise known as dative bond.
In covalent bond the electrons shared by both the atoms are contributed by both the atoms equally.
99. What Happens When Aminoacids React With Alcohols?
Ans:
when alcohols reats with aminoacids esters are formed. The esters are volatile in contrast to free aminoacids.
R-CH-COOH + H2O-C2H5 -> R-CH-COO-C2H5 + H2O
NH2 NH2
100. What Are Ligases?which Type Of Reactions They Will Catalyse?
Ans:
Ligases are the group of enzymes that catalyse the transfer of a group from one kind of molecule to another. These are also called transferases.
101. Nh2-ch2-cooh Belongs To What Structure?
Ans:
its the structure of amino acid glacine
102. Mention The Factors Affecting Solubility Of Compounds?
Ans:
temperature, pH, structure of compound i.e., whether the compd is straight chain or branched & molecular weight of compd.
103. What Are Geometrical Isomerism? Explain Them With An Example?
Ans:
Geometrical isomerism is an example of stereo-isomerism.
This occurs when substances have the same molecular formula, but a different arrangment of their atoms in space. There are three ways that this can happen:
where there is a C=C bond in the molecule;
where a molecule has rings; or
where there is a >C=N bond.
104. How ‘salting Out’ Process Is Used In Extraction?
Ans:
Proteins are precipitated from aqueous solution by high concentrations of neutral salts. This is the”salting -out” process.
Divalent and trivalent ions are more effective than univalent ions.
The salts commonly used for this purpose are NA2SO4,(NH4) 2SO4 Magnesium salts, and phosphates.
105. What Is Saponification Of Oils?
Ans:
When fats are hydrolysed with alkhali,the free fatty acids react with alkali to form metallic acids.these salts are soaps and this process is called saponification.
106. What Is Redox Potential Of An Organic Compound?
Ans:
The quantitative measure of the affinity of a compound to lose or gain electrons is the redox potential.
107. What Is Lithipone?
Ans:
Lithipone is a white pigment.it is amixture of BaSO4&ZnS.
108. What Is Difference Between Anti-aromatic And Non-aromatic Compounds?
Ans:
Anti aromatic compounds follows 4npi electron rule and are cyclic compounds, planar, where as non aromatic are non planar or planar, cyclic or acyclic.
109. What Is The Range Of Uv & Vis Lamp In Spectrophotometer?
Ans:
uv lamp range is 200 nm to 340 nm.
vis lamp range is 320 nm to 1100 nm.
both of lamp range is mfg instument company voice of record is enculd the data range in lamp is 200 nm to 1200 nm.
110. If Benzene And Tolune Both Can Be Mixed… What Is The Boiling Point For The Mixture And Its Density?
Ans:
If benzene and toluene mixed the boiling point will be ~ 90oC. Density will not change.
111. Benzoic Acid Is A Weaker Than Para Nitro Benzoic Acid?
Ans:
in p-nitrobenzoic acid due to -I effect of nitro group hydrogen present in acia become more elecronegative and easily remove as proton and act like strong acid.
112. What Is The Difference Between Sulphated Ash And Roi?
Ans:
There no difference between procedure, both are same. we generally term it as sulphated ash test/roi.in indian pharmacoepia, called it as roi and in usp, called it as sulphated ash tesh. both are used for the determination of content of inorganic matter in an organic substance.
113. If Tis Below Reaction Does Happaen Means…,what Is The End Product…….? Naphthal + Toluene(or)benzene?
Ans:
high molecular weight easily we can seperate koH
114. What Is The Difference Between Pvc And Upvc Plastic?
Ans:
PVC-POLYVINYL CHLORIDE AND uPVC IS THE Unplasticized polyvinyl chloride IT IS USED FOR building industry as a low-maintenance material.
115. What Mean By Organic Chemistry?
Ans:
Organic Chemistry is a branch of Science, which deals study about carbon compounds except Carbon monoxide, Carbon di oxide and corbonates.
116. Which Organic Compound Is Used As A Fuel In Jet Air Crafts? A. 100 Octane B. 90 Octane C. Kerosine Oil D. Diesel Oil
Ans:
Kerosine oil
117. What Is The Difference Between An Ion And A Radical?
Ans:
An ion is a specie that have no unpaired electron and is charged, either positively or negatively i.e. may be a cation or an anion. It is formed due to heterolysis of a molecule
e.g HCl—-> H+ + Cl-
A radical is a neutral specie having atleast one unpaired electron and is formed due to homolysis of a molecule
e.g H-H ——-> H* + H*
The * shows an unpaired electron. Similarly CH3* is a radical.
118. How To Synthsis Toluene To Benzaldehyde?
Ans:
from directly reaction of toluene to cromyl chloride (CrO2Cl2) at room temp. to form benzaldehyde.
119. How To Make A 100ml Solution With Given 10gm Of Naoh?
Ans:
Take 100ml water and pore 10gr NaOH pellets sterr with gently boil. NaOH sol ready.
120. How We Can Differentiate Between Oxalic Acid And Tartaric Acid?
Ans:
By Fluorescein test … where tartaric acid ” used in baking powder and found in many food products
oxalic acid : harmful in contact with skin or eyes toxic .remove Ca ions From blood and also block Kidneys Fluoresce in test depended on Light passes & usually in UV light
121. Equal masses of oxygen, hydrogen and methane are kept under identical conditions. The ratio of the volumes of gases will be
A.2 : 16 : 2
B.2 : 16 : 1
C.1 : 16 : 2
D.1 : 1 : 1
Ans:
C.1 : 16 : 2
122. The mass number of an atom is equal to
A.the number of protons
B.the number of protons and electrons
C.the number of nucleons
D.the number of neutrons
Ans:
C.the number of nucleons
123. The maximum number of covalent formed by nitrogen is
A.1
B.2
C.3
D.4
Ans:
D.4
124. The formula C6H5-CO-CH3 represents
A.Acetone
B.Acetic acid
C.Acetophenone
D.Phenyl acetate
Ans:
C.Acetophenone
125. The metal that is usually extracted from sea water is
A.Ca
B.Na
C.K
D.Mg
Ans:
D.Mg
126. The method of concentrating the ore which makes use of the difference in density between ore and impurities is called
A.liquation
B.leaching
C.levigation
D.magnetic separation
Ans:
C.levigation
127. The inert gases are ____ in water
A.sparingly soluble
B.insoluble
C.soluble
D.None of these
Ans:
A.sparingly soluble
128. The molecular formula of phosphorous is
A.P1
B.P2
C.P3
D.P4
Ans:
D.P4
129. Explain what is iron ore consists of?
Ans:
Iron ore is consists of Fe2O3
130. Explain what is dextro-rotatory and levo-rotatory?
Ans:
Levorotation and Dextrorotation is referred to the properties of plane polarized light, when light rotates clockwise when it approaches the observer is then known as dextro-rotation and when the light rotates anti-clockwise then it is referred as levo-rotation.
A compound which exhibits a dextro-rotation is referred as dextro-rotatory and which exhibits levo-rotation is referred as levo-rotatory.