UPSC CDS-2 Archives

11. Which of the following pairs of Indian State and tribal population are

Which of the following pairs of Indian State and tribal population are correct?

1. Madhya Pradesh : Largest tribal population
2. Mizoram : Highest percentage of tribal population out of the total population of the State
3. Chhattisgarh : Second largest tribal population after Madhya Pradesh
4. Arunachal Pradesh : Second highest percentage of tribal population out of the total population of the State after Mizoram

Select the correct answer using the code given below.

1 and 2 only

2 and 4 only

1, 2 and 3

2, 3 and 4

This question was previously asked in

UPSC CDS-2 – 2016

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The correct pairs are Madhya Pradesh having the largest tribal population by number and Mizoram having the highest percentage of tribal population.

– Statement 1 is correct: As per Census 2011, Madhya Pradesh has the largest Scheduled Tribe (ST) population by number in India.
– Statement 2 is correct: As per Census 2011, Mizoram has the highest percentage of ST population out of its total population.
– Statement 3 is incorrect: While Chhattisgarh has a significant tribal population, states like Maharashtra, Odisha, and Rajasthan have larger tribal populations by number than Chhattisgarh, after Madhya Pradesh. Maharashtra is typically ranked second.
– Statement 4 is incorrect: Arunachal Pradesh has a high percentage of tribal population, but states like Nagaland and Meghalaya have higher percentages than Arunachal Pradesh, after Mizoram.

The distribution and concentration of tribal populations vary greatly across India, influenced by geographical, historical, and socio-economic factors. Census data is the primary source for statistics on tribal populations.

12. With reference to earthquakes, which of the following statements are c

With reference to earthquakes, which of the following statements are correct?

1. Earthquakes largely occur along the converging plate boundaries.
2. Point of origin of earthquake in lithosphere is known as focus/hypocentre.
3. Intensity of earthquake decreases with distance from the epicentre.
4. Epicentre of earthquake always remains over continents only.

Select the correct answer using the code given below.

1 and 2 only

1, 2 and 3

2 and 3 only

1 and 4

This question was previously asked in

UPSC CDS-2 – 2016

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Statements 1, 2, and 3 correctly describe aspects of earthquakes. Statement 4 is incorrect.

1. Earthquakes are indeed largely concentrated along plate boundaries, especially convergent (subduction and collision zones) and transform boundaries, where tectonic stresses are highest.
2. The focus (or hypocentre) is the exact point within the Earth’s lithosphere where the seismic rupture originates.
3. The intensity of ground shaking and damage caused by an earthquake typically decreases as distance from the epicentre (the point on the surface directly above the focus) increases, as seismic waves lose energy as they travel.
4. Earthquakes occur in both continental and oceanic lithosphere. The epicentre can be located anywhere on the Earth’s surface, including over oceans (e.g., associated with mid-ocean ridges, oceanic trenches, or transform faults in oceanic crust).

The magnitude of an earthquake (e.g., on the Richter or Moment Magnitude scale) measures the energy released at the source, while intensity (e.g., on the Modified Mercalli scale) measures the effect of the earthquake on people, buildings, and the environment at a particular location.

13. According to Census 2011, which one of the following is the correct se

According to Census 2011, which one of the following is the correct sequence of States in decreasing order of their total size of population?

Kerala, Jharkhand, Assam, Punjab

Jharkhand, Kerala, Assam, Punjab

Kerala, Jharkhand, Punjab, Assam

Jharkhand, Kerala, Punjab, Assam

This question was previously asked in

UPSC CDS-2 – 2016

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According to the Census of India 2011 data, the total populations for the given states were approximately: Kerala (33.4 million), Jharkhand (32.9 million), Assam (31.2 million), and Punjab (27.7 million).

Arranging these populations in decreasing order:
Kerala (33.4 million)
Jharkhand (32.9 million)
Assam (31.2 million)
Punjab (27.7 million)
This order matches option A: Kerala, Jharkhand, Assam, Punjab.

Population data is a key demographic indicator captured by national censuses. For UPSC and similar exams, familiarity with the relative sizes and rankings of Indian states based on population, area, density, literacy, sex ratio, etc., is often required, especially for major states or those highlighted for specific reasons.

14. Which one of the following elements does not form solid hydrogen

Which one of the following elements does not form solid hydrogen carbonate?

Sodium

Potassium

Caesium

Lithium

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UPSC CDS-2 – 2016

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Lithium (Li) is the first element in the alkali metal group (Group 1). While other alkali metals (Sodium, Potassium, Rubidium, Caesium) form stable solid hydrogen carbonates (MΗCO₃), Lithium hydrogen carbonate (LiHCO₃) is significantly less stable as a solid.

LiHCO₃ exists in aqueous solution, but when attempts are made to isolate it as a solid, it readily decomposes upon heating or dehydration into lithium carbonate (Li₂CO₃), water (H₂O), and carbon dioxide (CO₂). This instability prevents the formation of a stable solid crystalline LiHCO₃ under normal conditions, unlike NaHCO₃, KHCO₃, CsHCO₃, etc., which are stable solids. This difference is often attributed to Lithium’s small ionic size and relatively high polarizing power (diagonal relationship with Magnesium).

The stability of alkali metal bicarbonates increases down the group. Sodium bicarbonate (baking soda) and Potassium bicarbonate are common solid compounds.

15. Excessive use of which of the following fertilizers may be responsible

Excessive use of which of the following fertilizers may be responsible for the presence of a toxic substance in groundwater?

Nitrogen

Phosphate only

Potassium only

Phosphate and potassium

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UPSC CDS-2 – 2016

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Excessive use of nitrogen fertilizers, particularly those containing nitrates or ammonium, can lead to the leaching of nitrates (NO₃⁻) into groundwater.

Nitrates are highly soluble and negatively charged, making them mobile in soil water and susceptible to leaching, especially in well-drained soils and areas with high rainfall or irrigation. Elevated levels of nitrates in drinking water are a human health concern, particularly for infants, as nitrates can be converted to nitrites in the digestive system, interfering with the blood’s oxygen-carrying capacity (causing methemoglobinemia). Phosphates are generally less mobile in soil due to adsorption to soil particles. Potassium is also relatively mobile but does not pose the same level of direct toxicity risk in drinking water as nitrates at common concentrations.

Nitrate contamination of groundwater is a significant environmental issue in agricultural regions worldwide. Other sources of nitrates include livestock manure and septic systems.

16. Deficiency of fluoride leads to which one of the following health

Deficiency of fluoride leads to which one of the following health problems?

Tooth caries

Mottling of tooth

Bending of bones

Stiffening of joints

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UPSC CDS-2 – 2016

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Fluoride plays a crucial role in dental health. It strengthens tooth enamel by incorporating into the crystal structure, forming fluorapatite, which is more resistant to acid dissolution than hydroxyapatite.

A deficiency of fluoride weakens tooth enamel, making teeth more susceptible to demineralization by acids produced by bacteria in the mouth. This process leads to the formation of cavities, known as tooth caries or tooth decay.

Mottling of teeth (dental fluorosis) is caused by *excessive* intake of fluoride during tooth development. Bending of bones (rickets) is typically due to Vitamin D, calcium, or phosphate deficiency. Stiffening of joints can be caused by various conditions like arthritis.

17. Dolomite powder is applied in some agricultural lands. The purpose of

Dolomite powder is applied in some agricultural lands. The purpose of applying it is to

increase the pH of the soil

lower the pH of the soil

increase the phosphorus content of the soil

increase the nitrogen content of the soil

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UPSC CDS-2 – 2016

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Dolomite is calcium magnesium carbonate (CaMg(CO₃)₂). Carbonate compounds are alkaline. When added to soil, they react with soil acidity (hydrogen ions), neutralizing it.

Applying dolomite to soil increases the soil’s pH, making it less acidic. This is often done in agricultural lands where the soil is too acidic for optimal plant growth. Dolomite acts as a liming agent and also provides essential nutrients, calcium and magnesium, to the soil.

Lowering soil pH is done using acidic substances like sulfur or aluminum sulfate. While dolomite contains calcium and magnesium, its primary role as a soil amendment is pH adjustment. It does not directly increase phosphorus or nitrogen content; these are supplied by phosphate and nitrogen fertilizers, respectively.

18. In paper manufacturing, degumming of the raw material is done using

In paper manufacturing, degumming of the raw material is done using

sulphuric acid

bleaching powder

caustic soda

nitric acid

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UPSC CDS-2 – 2016

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In paper manufacturing, the raw material (typically wood or plant fibres) contains not just cellulose but also lignin, hemicellulose, waxes, and other substances. “Degumming” is a process aimed at removing or breaking down unwanted non-cellulose components to obtain clean fibres suitable for papermaking. Alkaline solutions, such as caustic soda (sodium hydroxide, NaOH), are widely used in various pulping processes (like the Kraft process) to break down lignin and extract other materials, including some gummy substances or waxes, from the cellulose fibres.

Caustic soda is a strong alkali used in the pulping process to dissolve lignin and other impurities, separating the cellulose fibres. This process effectively “degums” or cleans the fibres before they are processed into paper. Bleaching powder is used for whitening the pulp after pulping. Sulphuric acid and nitric acid are strong acids with different applications (e.g., in chemical processing or nitration) and are not typically the primary agents for degumming in standard paper pulping, although acidic processes (like the sulfite process) exist, they target lignin and hemicellulose differently than the general removal of gummy substances often associated with alkaline treatments or specific fibre degumming steps.

Pulping processes, whether alkaline (like Kraft) or acidic (like Sulfite), aim to liberate cellulose fibers by removing lignin and other matrix components. While the term “degumming” is sometimes specifically used for fibres like cotton or hemp, the underlying chemical principle of using alkalis to remove impurities containing waxes, pectins, etc., is relevant to how caustic soda functions in cleaning paper pulp fibres.

19. Which one of the following is not an allotrope of carbon?

Which one of the following is not an allotrope of carbon?

Coal

Diamond

Graphite

Graphene

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UPSC CDS-2 – 2016

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Allotropes are different physical forms in which an element can exist in the same physical state. Diamond, Graphite, and Graphene are distinct structural forms of pure carbon.

Diamond, Graphite, and Graphene are well-known allotropes of carbon with different crystal structures and physical properties. For example, diamond is very hard with a tetrahedral structure, graphite is soft with a layered structure, and graphene is a single layer of carbon atoms in a hexagonal lattice.
Coal, however, is a naturally occurring fossil fuel composed primarily of carbon but also containing varying amounts of hydrogen, oxygen, nitrogen, sulfur, and other elements, as well as mineral matter. It is a complex mixture, not a pure element existing in a specific crystalline or amorphous form.

Other allotropes of carbon include fullerenes (like Buckyballs), carbon nanotubes, and amorphous carbon. Coal contains carbon but is chemically and structurally too complex to be considered an allotrope of carbon.

20. An irregular mode of reproduction resulting in the development of an e

An irregular mode of reproduction resulting in the development of an embryo without fertilization is called
1. Parthenogenesis
2. Apogamy
3. Sporophytic budding
Select the correct answer using the code given below.

1 only

2 only

2 and 3 only

1, 2 and 3

This question was previously asked in

UPSC CDS-2 – 2016

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The question describes apomixis, which is a form of asexual reproduction that mimics sexual reproduction by resulting in the formation of an embryo without fertilization. Parthenogenesis, Apogamy, and Adventitious embryony are all types of apomixis. While “Sporophytic budding” is not the most standard term, it is sometimes used to describe the development of embryos or embryo-like structures directly from sporophytic tissue, which falls under the umbrella of adventitious embryony, a form of apomixis. Given the options, it is likely intended to include different origins of apomictic embryos.

1. Parthenogenesis: Development of an embryo directly from an unfertilized egg cell.
2. Apogamy: Development of a sporophyte (embryo) from any gametophytic cell other than the egg (e.g., synergids, antipodal cells) without fertilization.
3. Sporophytic budding (or Adventitious embryony): Development of an embryo directly from diploid sporophytic cells (like nucellus or integument) without the formation of gametes or fertilization. If “sporophytic budding” refers to this, then all three processes result in an embryo without fertilization.

Apomixis is common in many plant species, including some important crop plants and wild relatives. It can lead to the production of clonal offspring.