UPSC CAPF Archives

41. The gas generated on reacting zinc with dilute sulphuric acid is :

The gas generated on reacting zinc with dilute sulphuric acid is :

[amp_mcq option1=”Argon” option2=”Helium” option3=”Hydrogen” option4=”Nitrogen” correct=”option3″]

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UPSC CAPF – 2023

When a reactive metal like zinc reacts with a dilute acid like sulphuric acid, it displaces hydrogen from the acid. The reaction is: Zn(s) + H₂SO₄(aq) -> ZnSO₄(aq) + H₂(g). This reaction produces zinc sulphate (a salt) and hydrogen gas.

Active metals react with dilute acids to produce hydrogen gas and a salt.

This is a standard method for preparing hydrogen gas in the laboratory. The hydrogen gas can be tested by bringing a burning splint near it; it will burn with a pop sound.

42. The common element in graphite, fullerene, diamond and graphene is :

The common element in graphite, fullerene, diamond and graphene is :

[amp_mcq option1=”Oxygen” option2=”Nitrogen” option3=”Hydrogen” option4=”Carbon” correct=”option4″]

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UPSC CAPF – 2023

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Graphite, fullerene, diamond, and graphene are all different structural forms of the element carbon. They are known as allotropes of carbon. Diamond has a tetrahedral structure, graphite has a layered hexagonal structure, fullerenes are cage-like molecules (e.g., C60), and graphene is a single layer of carbon atoms arranged in a hexagonal lattice. Therefore, the common element in all of them is carbon.

Allotropes are different structural modifications of an element; the atoms are bonded together in a different manner. Diamond, graphite, fullerenes, and graphene are allotropes of carbon.

The different structures of carbon allotropes result in vastly different physical and chemical properties. For instance, diamond is extremely hard and an electrical insulator, while graphite is soft and a good electrical conductor.

43. Which one of the following statements is correct?

Which one of the following statements is correct?

[amp_mcq option1=”Alloys are mixtures.” option2=”Alloys are compounds.” option3=”Alloys are always made up of metals.” option4=”All alloys contain carbon as one of their components.” correct=”option1″]

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An alloy is a metallic substance composed of two or more elements, at least one of which is a metal. It is typically formed by mixing molten components. Alloys are considered mixtures because their constituent elements are not chemically bonded in a fixed ratio throughout the material; their properties are a combination of the properties of the constituents, and they can often be separated by physical means. Option B is incorrect as alloys are mixtures, not compounds. Option C is incorrect as alloys can include non-metals (like carbon in steel). Option D is incorrect as many alloys do not contain carbon (e.g., brass is copper and zinc).

Alloys are physical mixtures of metals or metals and non-metals.

The properties of alloys often differ significantly from those of their constituent elements. For example, steel (iron and carbon) is much stronger than pure iron, and brass (copper and zinc) is harder than either copper or zinc.

44. The method used in separating a mixture of two miscible liquids having

The method used in separating a mixture of two miscible liquids having sufficient difference in their boiling points is :

[amp_mcq option1=”Filtration” option2=”Solvent Extraction” option3=”Centrifugation” option4=”Simple Distillation” correct=”option4″]

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UPSC CAPF – 2023

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Simple distillation is a laboratory technique used to separate a mixture of two miscible liquids with significantly different boiling points. When the mixture is heated, the component with the lower boiling point vaporizes first, its vapor is condensed, and collected as a separate liquid (distillate). The other options are methods used for different types of separations: Filtration separates solids from liquids/gases, Solvent Extraction separates substances based on differential solubility in immiscible solvents, and Centrifugation separates components of a mixture based on density difference.

Simple distillation is effective for separating miscible liquids with a significant difference in boiling points (typically > 25°C).

Fractional distillation is used when the difference in boiling points is smaller. Azeotropes are mixtures of liquids that boil at a constant temperature and cannot be separated by simple or fractional distillation.

45. Which of the following is/are not an official language(s) of the Unite

Which of the following is/are not an official language(s) of the United Nations ?

1. Arabic
2. German
3. Spanish
4. Chinese

Select the correct answer using the code given below :

[amp_mcq option1=”1 and 3 only” option2=”1 and 4 only” option3=”1 and 2 only” option4=”2 only” correct=”option4″]

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UPSC CAPF – 2023

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The official languages of the United Nations are Arabic, Chinese, English, French, Russian, and Spanish. Among the options provided, Arabic, Spanish, and Chinese are official UN languages, while German is not. The question asks which of the listed languages are *not* official. Only German (option 2) is not an official UN language from the given list. Therefore, the correct answer is option D, which selects “2 only”.

The six official languages of the United Nations are Arabic, Chinese, English, French, Russian, and Spanish.

These languages are used in official meetings and documents of the UN. While English and French are working languages of the UN Secretariat, all six are considered official languages for broader UN functions.

46. The National Human Rights Commission was established under the statute

The National Human Rights Commission was established under the statute of :

[amp_mcq option1=”The Protection of Human Rights Act, 1993″ option2=”The Protection and Implementation of Human Rights Act, 1993″ option3=”The Human Rights Act, 1993″ option4=”The Human Rights Commission Act, 1993″ correct=”option1″]

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UPSC CAPF – 2023

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The correct option is A) The Protection of Human Rights Act, 1993.

The National Human Rights Commission (NHRC) of India is a statutory body. It was established by an Act of Parliament, namely The Protection of Human Rights Act, 1993. This Act provides the legal framework for the establishment and functioning of the NHRC and State Human Rights Commissions (SHRCs) in India.

A statutory body is a body set up by a legislative act, not directly by the constitution. The Protection of Human Rights Act, 1993 was enacted to provide for the constitution of a National Human Rights Commission, State Human Rights Commissions and Human Rights Courts for better protection of human rights and for matters connected therewith or incidental thereto.

47. Which of the following statements about Quad is/are correct ? 1. It

Which of the following statements about Quad is/are correct ?

1. It is a group of four countries, namely, India, Australia, USA and France.
2. Maritime cooperation is an important binding force among members of the Quad.
3. The Quad members formed a working group on COVID-19 vaccines.

Select the correct answer using the code given below :

[amp_mcq option1=”1 only” option2=”1 and 2 only” option3=”2 and 3 only” option4=”1, 2 and 3″ correct=”option3″]

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UPSC CAPF – 2023

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The correct option is C) 2 and 3 only.

Statement 1: It is a group of four countries, namely, India, Australia, USA and France. This is incorrect. The Quad, or Quadrilateral Security Dialogue, is an informal strategic forum comprising four countries: India, Japan, Australia, and the United States. France is not a member.
Statement 2: Maritime cooperation is an important binding force among members of the Quad. This is correct. Maritime security, freedom of navigation, and counter-piracy efforts in the Indo-Pacific region are key pillars of Quad cooperation, often involving joint naval exercises like Malabar.
Statement 3: The Quad members formed a working group on COVID-19 vaccines. This is correct. During their first leaders’ summit in March 2021, the Quad announced a partnership to accelerate the manufacturing and delivery of COVID-19 vaccines to countries in the Indo-Pacific, establishing a working group for this purpose.

The Quad is not a formal military alliance but rather a diplomatic network for consultation and cooperation on issues of mutual interest, particularly regarding the Indo-Pacific region. Its agenda has broadened beyond security to include areas like critical and emerging technologies, climate change, infrastructure, and global health security (like the vaccine initiative).

48. Which of the following statements about Organization for Security and

Which of the following statements about Organization for Security and Cooperation in Europe (OSCE) are correct ?

1. There are total 57 states from Europe, Central Asia and America.
2. It offers a forum for political negotiations and decision-making in the field of early warning, conflict prevention, crisis management and post-conflict rehabilitation.
3. OSCE has the primary responsibility of providing military security in the European Region.
4. The decisions of OSCE are legally binding.

Select the correct answer using the code given below :

[amp_mcq option1=”1 and 2 only” option2=”1, 2 and 3 only” option3=”1, 2, 3 and 4″ option4=”3 and 4 only” correct=”option1″]

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The correct option is A) 1 and 2 only.

Statement 1: There are total 57 states from Europe, Central Asia and America. This is correct. The Organization for Security and Cooperation in Europe (OSCE) is indeed the world’s largest security-oriented intergovernmental organization, with 57 participating states from Europe, Central Asia, and North America.
Statement 2: It offers a forum for political negotiations and decision-making in the field of early warning, conflict prevention, crisis management and post-conflict rehabilitation. This is correct. These functions are central to the OSCE’s comprehensive approach to security, covering the politico-military, economic-environmental, and human dimensions.
Statement 3: OSCE has the primary responsibility of providing military security in the European Region. This is incorrect. NATO (North Atlantic Treaty Organization) is the primary military alliance responsible for collective defense in the Euro-Atlantic area. The OSCE’s role in the politico-military dimension focuses more on arms control, confidence-building measures, and border management, not primary military security provision.
Statement 4: The decisions of OSCE are legally binding. This is incorrect. Decisions in the OSCE are taken by consensus among all participating states and are politically binding, not legally binding under international law.

The OSCE operates through a consensus-based decision-making process. Its comprehensive concept of security addresses a wide range of security-related concerns, including arms control, preventive diplomacy, confidence and security-building measures, human rights, democratization, and economic and environmental activities.

49. Sixty-four cubes of sides 2 cm each are combined to form a cube of sid

Sixty-four cubes of sides 2 cm each are combined to form a cube of side 8 cm. If four of the smaller cubes along the diagonal of a surface are removed from the surface of the large cube, which one of the following statements about the surface area of this solid object is true ?

[amp_mcq option1=”It is equal to the surface area of the large cube.” option2=”It is less than the surface area of the large cube.” option3=”It is more than the surface area of the large cube.” option4=”Insufficient data” correct=”option3″]

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The correct option is C) It is more than the surface area of the large cube.

A large cube of side 8 cm is formed from 64 smaller cubes of sides 2 cm (8/2 = 4, so it’s a 4x4x4 arrangement of small cubes).
The surface area of the large cube is 6 * (8 cm)^2 = 6 * 64 sq cm = 384 sq cm.
Four smaller cubes are removed along the diagonal of a surface (face) of the large cube. Consider one face as a 4×4 grid of the smaller cubes’ exposed faces. The diagonal consists of the 4 cubes at positions (0,0), (1,1), (2,2), (3,3) in this grid (assuming indexing from a corner 0,0).
These 4 small cubes correspond to positions in the 4x4x4 large cube grid. Let’s say the face is the top face (z=3, using 0-3 indexing). The cubes are (0,0,3), (1,1,3), (2,2,3), (3,3,3).
– Cubes (0,0,3) and (3,3,3) are corner cubes of the large cube assembly (3 faces originally exposed on the large cube’s surface).
– Cubes (1,1,3) and (2,2,3) are ‘face’ cubes of the large cube assembly (1 face originally exposed on the large cube’s surface).

When a small cube is removed from the surface of the large cube:
– Surface area is lost from the original surface of the large cube.
– New surface area is gained from the faces of the removed small cube that were previously internal.

– For a corner cube (like (0,0,3) or (3,3,3)): 3 faces (each 2×2=4 sq cm) were exposed on the large cube surface (total 12 sq cm). When removed, the 3 interior faces become exposed (total 12 sq cm). Net change in surface area = -12 + 12 = 0.
– For a face cube (like (1,1,3) or (2,2,3)): 1 face (4 sq cm) was exposed on the large cube surface. When removed, the 5 interior faces become exposed (total 5 * 4 = 20 sq cm). Net change in surface area = -4 + 20 = +16 sq cm.

The four removed cubes consist of 2 corner cubes and 2 face cubes of the large cube assembly.
Total change in surface area = (2 * Change from corner cube) + (2 * Change from face cube)
Total change = (2 * 0) + (2 * +16 sq cm) = 0 + 32 sq cm = +32 sq cm.

The surface area of the solid object after removing the cubes is the original surface area plus the net change.
New Surface Area = 384 sq cm + 32 sq cm = 416 sq cm.

Since the new surface area (416 sq cm) is greater than the original surface area (384 sq cm), the surface area of this solid object is more than the surface area of the large cube. The removal of cubes, especially from non-corner positions on a face or edge, typically increases the total surface area by exposing internal faces.

50. If x and y are two-digit prime numbers such that y is obtained from x

If x and y are two-digit prime numbers such that y is obtained from x by interchanging its digits and x – y = 36, then what is the value of xy ?

[amp_mcq option1=”1611″ option2=”2701″ option3=”4031″ option4=”5603″ correct=”option2″]

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UPSC CAPF – 2023

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The correct option is B) 2701.

Let the two-digit prime number x be represented as 10a + b, where ‘a’ is the tens digit and ‘b’ is the units digit. Both ‘a’ and ‘b’ are integers between 1 and 9, since x is a two-digit number and b cannot be 0 if the reversed number y is also two digits.
The number y is obtained by interchanging the digits, so y = 10b + a.
Both x and y must be prime numbers.
We are given that x – y = 36.
(10a + b) – (10b + a) = 36
9a – 9b = 36
9(a – b) = 36
a – b = 4.

We need to find two digits a and b (1-9) such that a – b = 4, and both (10a + b) and (10b + a) are prime numbers.
Let’s list the possible pairs (a, b) where a – b = 4:
– If b = 1, a = 5. x = 51 (51 = 3 * 17, not prime).
– If b = 2, a = 6. x = 62 (not prime).
– If b = 3, a = 7. x = 73. 73 is a prime number. y = 37. 37 is a prime number. This pair (a=7, b=3) satisfies all conditions.
– If b = 4, a = 8. x = 84 (not prime).
– If b = 5, a = 9. x = 95 (not prime).

The only pair of digits satisfying the conditions is a=7 and b=3.
So, x = 73 and y = 37.
Check: x and y are two-digit prime numbers. x – y = 73 – 37 = 36. All conditions met.

The question asks for the value of xy.
xy = 73 * 37.
Calculation:
73 * 37 = 73 * (30 + 7) = 73 * 30 + 73 * 7
= 2190 + 511
= 2701.

It’s important to systematically check all possible digit pairs that satisfy the difference condition and then verify the primality of both the original and reversed numbers. Recalling common two-digit prime numbers helps in quickly checking the candidates.