Explore topic-wise MCQs in UPSC IAS Exam.

This section includes 351 Mcqs, each offering curated multiple-choice questions to sharpen your UPSC IAS Exam knowledge and support exam preparation. Choose a topic below to get started.

1.

The chemical formula of plaster of parts is                           [BPSC]

A. \[CaS{{O}_{4}}.5{{H}_{2}}O\]
B. \[2CaS{{O}_{4}}.{{H}_{2}}O\]
C. \[(CaS{{O}_{4}}).2{{H}_{2}}O\]
D. \[COSO4.MGO\]
Answer» D. \[COSO4.MGO\]
2.

The chemical name of lime stone is                           [UPPCS]

A. Calcium chloride
B. Calcium oxide
C. Calcium carbonate
D. Calcium
Answer» D. Calcium
3.

What type of mixture is smoke?                       [CDS]

A. Solid mixed with a gas
B. Gas mixed with a gas
C. Liquid mixed with a gas
D. Gas mixed with a liquid and a solid
Answer» E.
4.

Iron sheet kept in moist air covered with rust. Rust is                       [CDS]

A. an element
B. a compound
C. a mixture of iron and dust
D. a mixture of iron, oxygen and water
Answer» C. a mixture of iron and dust
5.

Which one of the following petroleum refinery products has the lowest boiling point?                           [CDS]

A. Kerosene
B. Diesel
C. Gasoline
D. Lubricating oil
Answer» D. Lubricating oil
6.

Which one of the following is not a mixture?                        [CDS]

A. Toot paste
B. Toilet soap
C. Baking soda
D. Vinegar
Answer» D. Vinegar
7.

Which one of the following is used in the preparation of antiseptic solution?                    [CDS]

A. Potassium nitrate
B. Iodine
C. Iodine chloride
D. Potassium chloride
Answer» C. Iodine chloride
8.

Aqua-regia used by alchemists to separate silver and gold is a mixture of                       [CDS]

A. hydrochloric acid (concentrated) and nitric acid (concentrated)
B. hydrochloric acid  (concentrated) and sulphuric acid (concentrated)
C. nitric acid (concentrated) and sulphuric acid (concentrated)
D. hydrochloric acid (dilute) and sulphuric acid (dilute)
Answer» B. hydrochloric acid  (concentrated) and sulphuric acid (concentrated)
9.

What is the number of mole(s) of \[{{H}_{2}}\](g) required to saturate one mole benzene?                          [NDA]

A. 1
B. 2
C. 3
D. 4
Answer» D. 4
10.

How many moles of hydrogen atom are present in one mole of Aluminium hydroxide?                       [NDA]

A. One mole
B. Two moles
C. Three moles
D. Four moles
Answer» D. Four moles
11.

Which of the following statements regarding oxidation and reduction are correct? [NDA] 1. In oxidation, loss of electron takes place whereas in reduction, gain of electron takes place. 2. In oxidation, gain of electron takes place whereas in reduction, loss of electron takes place. 3. Oxidizing agent decreases the oxidation number but reducing agent increases the oxidation number. 4. Oxidizing agent increases the oxidation number but reducing agent reduces the oxidation number.                                       Select the correct answer using the code given below: Code:

A. 1 and 3
B. 2 and 4
C. 2 and 3
D. 1 and 4
Answer» E.
12.

Which is the symbol of the element tungsten?                       [NDA]

A. Ta
B. Tc
C. W
D. V
Answer» D. V
13.

Which of the following is the best example of the law of conservation of mass?                        [NDA]

A. When 12 gm. of carbon is heated in vacuum, there is no change in mass
B. Weight of platinum wire is the same before and after heating
C. A sample of air increases in volume when heated at constant pressure but mass remains unchanged
D. 12 gm. of carbon combines with 32 gm. Of oxygen to, give 44 gm. of carbon dioxide.
Answer» B. Weight of platinum wire is the same before and after heating
14.

In which one of the following situations a chemical reaction does not occur?                            [NDA]

A. Common salt is exposed to air
B. Coal is burnt in air
C. Sodium is placed in water
D. Iron is kept in moist air
Answer» B. Coal is burnt in air
15.

The following questions consist of two statements, one labelled as the Assertion [A] and the other as Reason (R), You are to examine these two statements carefully and select the answers to these items using the codes given below:                         [NDA] Assertion [A]: Atomic weights of most of the elements are not whole numbers. Reason (R): Atoms of most of the elements contain mixture of isotopes having different atomic weights.

A. Both A and R are individually true and R is the correct explanation of A
B. Both A and R are individually true but R is NOT the correct explanation of A
C. A is true but R is false
D. A is false but R is true
Answer» B. Both A and R are individually true but R is NOT the correct explanation of A
16.

An oxide of nitrogen has molecular weight 30. What is the number of electrons in one molecule of the compound?                       [NDA]

A. 14
B. 15
C. 22
D. 23
Answer» D. 23
17.

Which one of the following is not a mixture?                        [NDA]

A. Air
B. Mercury
C. Milk
D. Cement
Answer» C. Milk
18.

Which one among the following statements regarding the properties of mixtures and compounds is not correct?                                                                  [NDA]

A. A mixture shows the properties of its constituents but the properties of a compound are entirely different from its constituents
B. A mixture may be homogeneous or heterogeneous but a compound is a homogeneous substance
C. The constituents of a mixture can be separated by physical methods but those of a compound cannot be separated by physical methods
D. Energy is either absorbed or evolved during the preparation of a mixture but not in the preparation of a compound
Answer» E.
19.

Which one among the following is correct regarding \[{}^{20}Ne,{}^{23}N{{a}^{+}},{}^{19}{{F}^{-}}and\,\,{}^{24}M{{g}^{2+}}\]?                        [CDS]

A. They are isomers of each other
B. They are isotopes of each other
C. They are isoelectronic with each other
D. All of the above
Answer» D. All of the above
20.

The latest discovered state of matter is                       [NDA]

A. solid
B. Bose-Einstein condensation
C. plasma
D. liquid
Answer» D. liquid
21.

The nucleus of a singly ionized carbon atom contains                      [NDA]

A. 6 protons and 6 neutrons
B. 5 protons and 6 neutrons
C. 6 protons, 6 neutrons and 6 electrons
D. 12 protons, 6 neutrons and 6 electrons
Answer» B. 5 protons and 6 neutrons
22.

The number of neutrons in \[_{7}A{{I}^{27}}\] is                       [NDA]

A. 40
B. 27
C. 14
D. 13
Answer» D. 13
23.

An atom of carbon has 6 protons. Its mass number is 12. How many neutrons are present in an atom of carbon?                        [NDA]

A. 12
B. 6
C. 10
D. 14
Answer» C. 10
24.

Which one among the following transitions of electron of hydrogen atom emits radiation of the shortest wavelength?                     [NDA]

A. n = 2 to n = 1
B. n = 3 to n = 2
C. n = 4 to n = 3
D. n = 5 to n = 4
Answer» B. n = 3 to n = 2
25.

Which one among the following is correct regarding \[{}^{20}Ne,{}^{23}N{{a}^{+}},{}^{19}{{F}^{-}}and\,\,{}^{24}M{{g}^{2+}}\]?                        [NDA]

A. They are isomers of each other
B. They are isotopes of each other
C. They are isoelectronic with each other
D. All of the above
Answer» D. All of the above
26.

Which of the following is a good lubricant?                           [CDS]

A. Diamond powder
B. Graphite powder
C. Molten carbon
D. Alloy of carbon and iron
Answer» C. Molten carbon
27.

To weld metals together, high temperature is required. Such a high temperature is obtained by burning                     [NDA]

A. Acetylene in oxygen
B. LPG in oxygen
C. Methane in oxygen
D. Acetylene in nitrogen
Answer» B. LPG in oxygen
28.

Which one of the following is heavy water used in nuclear reactor?                      [CDS]

A. Water having molecular weight 18 u
B. Water having molecular weight 20 u
C. Water at \[4{}^\circ C\] but having molecular weight 19u
D. Water below the ice in a frozen sea
Answer» C. Water at \[4{}^\circ C\] but having molecular weight 19u
29.

Heavy water implies                   [CDS]

A. water which is used in heavy industries such as thermal power plants
B. water which contains \[S{{O}_{4}}^{2-}\] and \[C{{I}^{-}}\] of calcium and magnesium
C. deuterated water
D. water which has maximum density
Answer» D. water which has maximum density
30.

Which one of the following is not needed in a nuclear fission reactor?                             [CDS]

A. Moderator
B. Coolant
C. Accelerator
D. Control device
Answer» D. Control device
31.

Which one of the following reactions is the main cause of the energy radiation from the Sun?                        [CDS]

A. Fusion reaction
B. Fission reaction
C. Chemical reaction
D. Diffusion reaction
Answer» B. Fission reaction
32.

Age of fossil may be found out by determining the ratio of two isotopes of carbon. The isotopes are                        [CDS]

A. C-12 and C-13
B. C-13 and C-14
C. C-12 and C-14
D. C-12 and carbon black
Answer» D. C-12 and carbon black
33.

Which one of the following is correct? Butter is                     [CDS]

A. a super cooled oil
B. an emulsion
C. a molecular solid
D. None of these
Answer» E.
34.

The atomic weights are expressed in terms of atomic mass unit. Which one of the following is used as a standard?                                      [NDA]

A. \[^{\text{1}}{{\text{H}}_{\text{1}}}\]
B. \[^{\text{12}}{{C}_{6}}\]
C. \[^{\text{16}}{{O}_{8}}\]
D. \[^{35}C{{I}_{17}}\]
Answer» C. \[^{\text{16}}{{O}_{8}}\]
35.

Which one of the following elements shows variable equivalent mass?                            [NDA]

A. Zinc
B. Silver
C. Calcium
D. Iron
Answer» E.
36.

Which one of the following mixtures is homogeneous?                     [NDA]

A. Starch and sugar
B. Methanol and water
C. Graphite and charcoal
D. Calcium carbonate and calcium bicarbonate
Answer» C. Graphite and charcoal
37.

Which chemical was an important symbol in our freedom struggle?                      [CDS]

A. Glucose
B. Fertilizer
C. Medicine
D. Sodium chloride
Answer» C. Medicine
38.

The atomic weights are expressed in terms of atomic mass unit. Which one of the following is used as a standard?                        [NDA]

A. \[^{1}{{H}_{1}}\]
B. \[^{12}{{C}_{6}}\]
C. \[^{16}{{O}_{8}}\]
D. \[^{35}C{{I}_{17}}\]
Answer» C. \[^{16}{{O}_{8}}\]
39.

What is the number of water molecules present in a tiny drop of water (volume 0.0018 ml) at room temperature?                         [NDA]

A. \[4.84\times {{10}^{17}}\]
B. \[4.184\times {{10}^{18}}\]
C. \[6.023\times {{10}^{19}}\]
D. \[6.023\times {{10}^{23}}\]
Answer» D. \[6.023\times {{10}^{23}}\]
40.

What is the weight of one atom of Hydrogen in grams?                             [NDA]

A. \[6.023\text{ }\times \text{1}{{\text{0}}^{-23}}\]
B. \[1.66\text{ }\times \text{1}{{\text{0}}^{-24}}\]
C. \[6.62\text{ }\times \text{1}{{\text{0}}^{-24}}\]
D. None of these
Answer» C. \[6.62\text{ }\times \text{1}{{\text{0}}^{-24}}\]
41.

Blue vitriol is                    [UPPCS]

A. Copper sulphate
B. Calcium sulphate
C. Iron sulphate
D. Sodium sulphate
Answer» B. Calcium sulphate
42.

The main component of Gobar gas is?                       [CDS]

A. Chlorine
B. Hydrogen
C. Ethylene
D. Methene
Answer» E.
43.

Which one among the following is a sin smelling agent added to LPG cylinder to help the detection of gas leakage?                       [CDS]

A. Ethanol
B. Thioethanol
C. Methane
D. Chloroform
Answer» C. Methane
44.

Vermicompost is an/a                           [CDS]

A. inorganic fertilizer
B. toxic substance
C. organic bio fertilizer
D. synthetic fertilizer
Answer» D. synthetic fertilizer
45.

Nail polish remover contains                           [CDS]

A. acetone
B. benzene
C. formaldehyde
D. acetic acid
Answer» B. benzene
46.

Which one among the following statements about an atom is not correct?                      [CDS]

A. Atoms always combine to form molecules
B. Atoms are the basic units from which molecules and ions are formed
C. Atoms are always neutral in nature
D. Atoms aggregate in large numbers to form the matter that we can see, feel and touch
Answer» E.
47.

At NTP, the least volume will be occupied by 15 g of which one of the following?                     [NDA]

A. \[N{{H}_{3}}\]
B. \[{{O}_{2}}\]
C. \[{{N}_{2}}\]
D. Ne
Answer» D. Ne
48.

Iodised salt is a                          [CDS]

A. mixture of potassium iodide and common salt
B. mixture of molecular iodide and common salt
C. compound formed by combination of potassium  iodide and common salt
D. compound formed by molecular iodine and common salt
Answer» D. compound formed by molecular iodine and common salt
49.

Which of the following isotopes of carbon is/are used in carbon dating?                          [CDS]

A. \[_{6}{{C}^{12}}\] only
B. \[_{6}{{C}^{13}}\] only
C. \[_{6}{{C}^{14}}\] only
D. \[_{6}{{C}^{12}}\] and \[_{6}{{C}^{14}}\]
Answer» D. \[_{6}{{C}^{12}}\] and \[_{6}{{C}^{14}}\]
50.

An \[\alpha \]-particle consists of which of the following?                           [CDS]

A. 2 protons and 2 neutrons
B. 1 proton and 1 electron
C. 2 protons and 4 neutrons
D. 1 proton and 1 neutron
Answer» B. 1 proton and 1 electron