UPSC CDS-1

31. Which one among the following countries is not part of the Arabian

Which one among the following countries is not part of the Arabian Peninsula?

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Kuwait
Oman
Jordan
Yemen
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The Arabian Peninsula is a major landmass in Southwest Asia.
The countries typically considered part of the Arabian Peninsula are Saudi Arabia, Yemen, Oman, United Arab Emirates, Qatar, Bahrain, and Kuwait. Jordan is located north of the peninsula and is generally included in the broader Middle East region, often specifically the Levant, but not the Arabian Peninsula itself.
The Arabian Peninsula is bordered by the Red Sea, the Arabian Sea, the Gulf of Oman, and the Persian Gulf. It is the largest peninsula in the world.

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32. Which one of the following is known as cetane?

Which one of the following is known as cetane?

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Hexadecane
Heptadecane
Octadecane
Nonadecane
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Cetane is a term used in the context of diesel fuel quality.
Cetane is the common name for the alkane molecule hexadecane (C₁₆H₃₄). It is used as a reference standard with a high cetane number (defined as 100) to evaluate the ignition quality of diesel fuel.
The cetane number is a measure of a diesel fuel’s autoignition delay time. Fuels with higher cetane numbers ignite more readily under compression, leading to smoother engine operation.

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33. Which one of the following is related to global dimming?

Which one of the following is related to global dimming?

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Fall of atmospheric pressure due to increased particulates
Raise of atmospheric pressure due to increased particulates
Raise of temperature due to increased particulates
Fall of temperature due to increased particulates
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Global dimming is the reduction in the amount of solar radiation reaching the Earth’s surface.
This phenomenon is caused by increased levels of particulate matter (aerosols and pollutants) in the atmosphere. These particles reflect sunlight back into space and absorb solar radiation. They also act as cloud condensation nuclei, leading to brighter and more reflective clouds. By reducing the amount of incoming solar energy, global dimming results in a cooling effect, causing a fall of temperature at the Earth’s surface.
Global dimming has, to some extent, offset the warming effects of greenhouse gases. Changes in air pollution levels can therefore influence global temperature trends.

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34. Vinegar is

Vinegar is

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5-8% solution of acetic acid in water
5-8% solution of carbonic acid in water
5-8% solution of ethanol in water
10-15% solution of propionic acid in water
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Vinegar is a common acidic liquid produced through the fermentation of ethanol.
Vinegar is an aqueous solution of acetic acid (CH₃COOH). The concentration of acetic acid in most commercially available vinegars ranges from 5% to 8%, although some types may have higher concentrations (up to 20%).
The fermentation process typically involves two steps: alcoholic fermentation of sugars into ethanol by yeasts, followed by oxidation of ethanol to acetic acid by acetic acid bacteria (Acetobacter). Vinegar is used in cooking, preservation, and cleaning.

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35. Methanol is toxic because

Methanol is toxic because

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methanol coagulates the protoplasm
methanol gets oxidised to methanal in liver which coagulates the protoplasm
methanol gets oxidised to acetic acid in liver which coagulates the protoplasm
methanol gets oxidised to CO in liver which coagulates the protoplasm
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Methanol is toxic because it is metabolized into highly toxic substances in the body.
In the liver, methanol is oxidized by the enzyme alcohol dehydrogenase primarily into formaldehyde, which is also known as methanal. Formaldehyde is a potent toxin that can damage tissues, including causing the denaturation and coagulation of proteins, which is akin to coagulating protoplasm. Formaldehyde is further oxidized to formic acid, which contributes to metabolic acidosis.
The accumulation of formaldehyde and formic acid leads to the severe symptoms of methanol poisoning, including visual impairment (blindness), neurological damage, and potentially death.

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36. Which one of the following is the correct order of reactivity of Mg, A

Which one of the following is the correct order of reactivity of Mg, Al, Zn and Fe with HCl?

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”Mg
”Mg
”Zn
”Fe
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The reactivity of metals with dilute acids like HCl to displace hydrogen depends on the position of the metal in the reactivity series. Metals higher in the series are more reactive.
The standard reactivity series (based on standard electrode potentials) places these metals in the order of decreasing reactivity as Mg > Al > Zn > Fe > H. Therefore, their reactivity with HCl follows the same order: Mg > Al > Zn > Fe.
While Aluminium is theoretically more reactive than Zinc, its reaction with acids can sometimes be slower than expected due to the formation of a protective oxide layer on its surface. However, the fundamental order of reactivity based on standard potentials remains Mg > Al > Zn > Fe.

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37. The correct order of octane number of butane, pentane, hexane and cycl

The correct order of octane number of butane, pentane, hexane and cyclohexane is

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”butane
”butane
”butane
”cyclohexane
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Octane number is a measure of a fuel’s resistance to knocking. Branched hydrocarbons and cyclic hydrocarbons have higher octane numbers than straight-chain hydrocarbons with the same number of carbon atoms. The octane number decreases with increasing chain length for straight-chain alkanes.
Comparing the standard (n-) forms:
n-Butane (C4H10) has a higher octane number than n-pentane (C5H12) and n-hexane (C6H14).
n-Pentane has a higher octane number than n-hexane.
Cyclohexane (C6H12), a cyclic alkane, has a higher octane number than the corresponding straight-chain alkane, n-hexane, and typically higher than n-pentane.
The typical order of RON (Research Octane Number) is approximately: n-Butane (~92) > Cyclohexane (~83) > n-Pentane (~62) > n-Hexane (~25).
Thus, the correct order of decreasing octane number is butane > cyclohexane > pentane > hexane.
Octane number is inversely related to chain length for n-alkanes and higher for branched/cyclic structures compared to straight chains.
Octane numbers are determined relative to two reference hydrocarbons: isooctane (2,2,4-trimethylpentane), assigned an octane number of 100 (highly resistant to knocking), and n-heptane, assigned an octane number of 0 (knocks readily). The octane number of a fuel is the percentage of isooctane in a mixture with n-heptane that has the same knocking characteristics as the fuel.

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38. Which one of the following is an amphoteric oxide?

Which one of the following is an amphoteric oxide?

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MgO
P₄O₁₀
Na₂O
Al₂O₃
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An amphoteric oxide is one that exhibits both acidic and basic properties, meaning it can react with both acids and bases to form salts. Aluminium oxide (Al₂O₃) is a common example of an amphoteric oxide. It reacts with acids like HCl to form aluminium chloride and water (basic behaviour) and with bases like NaOH to form sodium aluminate (acidic behaviour).
Amphoteric oxides react with both acids and bases. Aluminium oxide (Al₂O₃) is an amphoteric oxide.
MgO (Magnesium oxide) and Na₂O (Sodium oxide) are basic oxides, typical of alkali and alkaline earth metal oxides. P₄O₁₀ (Phosphorus pentoxide) is an acidic oxide, typical of non-metal oxides, reacting with water to form phosphoric acid and with bases to form phosphates.

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39. If India enters into Free Trade Agreements (FTAs) with other nations,

If India enters into Free Trade Agreements (FTAs) with other nations, then the growth of exports of India would depend upon which of the following?

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  • 1. Extent of tariff reduction vis-à-vis MFN tariffs
  • 2. Extent of relaxation in terms of rules of origin
  • 3. Extent of relaxation in sanitary and phytosanitary measures
  • 4. Level of infrastructure in India
  • 5. Income in nations with which India enters into FTAs

Select the correct answer using the code given below.

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1, 3 and 4 only
1, 2 and 4 only
2, 3 and 5 only
1, 2, 3, 4 and 5
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All five factors listed are crucial determinants of India’s export growth under Free Trade Agreements (FTAs).
1. **Extent of tariff reduction:** Lower tariffs make Indian goods more competitive in partner markets.
2. **Rules of origin:** Lenient RoO ensure that a higher proportion of goods manufactured in India qualify for preferential FTA tariffs.
3. **Sanitary and phytosanitary measures:** Relaxations or clear standards for SPS measures facilitate exports of agricultural and food products.
4. **Infrastructure in India:** Efficient logistics, transportation, and port infrastructure reduce costs and improve reliability for exporters.
5. **Income in partner nations:** Higher economic growth and income levels in FTA partner countries lead to increased demand for imports, including those from India.
The success of export growth under FTAs depends not only on tariff reductions but also on non-tariff barriers, domestic capabilities, and market demand in partner countries.
Beyond these factors, other elements like trade facilitation measures, dispute resolution mechanisms within the FTA, currency exchange rates, and global economic conditions also play a role in influencing export performance.

40. Consider the following statements regarding weightage of different art

Consider the following statements regarding weightage of different articles in Wholesale Price Index (WPI) :

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  • 1. Fuel and power have higher weightage in WPI than that of primary articles.
  • 2. Weightage of manufactured products in WPI is higher than that of fuel and power.

Which of the statements given above is/are correct?

1 only
2 only
Both 1 and 2
Neither 1 nor 2
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Statement 1 is incorrect: In the Wholesale Price Index (WPI) structure for India (based on the 2011-12 series), the weightage of Primary Articles is approximately 22.62%, while the weightage of Fuel & Power is approximately 13.15%. Therefore, Fuel and Power have lower weightage than Primary Articles.
Statement 2 is correct: The weightage of Manufactured Products is the highest among the three broad groups, approximately 64.23%. This is significantly higher than the weightage of Fuel & Power (13.15%).
Manufactured Products have the highest weightage in WPI, followed by Primary Articles, and then Fuel & Power (based on 2011-12 series).
The WPI weights are revised periodically to reflect changes in the composition of wholesale trade in the economy. The current series (2011-12) is based on this distribution. This weightage structure is important for understanding which sectors’ price changes have the most impact on the overall WPI.

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