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9E) Chemistry (Prelims PYQs)

8E) Chemistry (Prelims PYQs)

2023 Prelims PYQs

1] Consider the following statements: [2023]

1. Carbon fibres are used in the manufacture of components used in automobiles and aircrafts.
2. Carbon fibres once used cannot be recycled.

Which of the statements given above is/are correct?
a) 1 only
b) 2 only
c) Both 1 and
d) Neither 1 nor 2

Show Answer

Ans: a) 1 only

2022 Prelims PYQs

1] With reference to polyethylene terephthalate, the use of which is so widespread in our daily lives, consider the following statements: [2022]

1. Its fibres can be blended with wool and cotton fibres to reinforce their properties.
2. Containers made of it can be used to store any alcoholic beverage.
3. Bottles made of it can be recycled into other products.
4. Articles made of it can be easily disposed of by incineration without causing greenhouse gas emissions.

Which of the statements given above are correct?
a) 1 and 3
b) 2 and 4
c) 1 and. 4
d) 2 and 3

Show Answer

Ans: a) 1 and 3

2021 Prelims PYQs

1] Bisphenol A (BPA), a cause of concern, is a structural/key component in the manufacture of which of the following kinds of plastics? [2021]

a) Low-density polyethylene
b) Polycarbonate
c) Polyethylene terephthalate
d) Polyvinyl chloride

Show Answer

Ans: b) Polycarbonate

2] Water can dissolve more substances than any other liquid because: [2021]

a) It is dipolar in nature
b) It is a good conductor of heat
c) It has high value of specific heat
d) It is an oxide of hydrogen

Show Answer

Ans: a) It is dipolar in nature

2019 Prelims PYQs

1] In the context of which one of the following are the terms ‘pyrolysis and plasma gasification’ mentioned? [2019]

a) Extraction of rare earth elements
b) Natural gas extraction technologies
c) Hydrogen fuel-based automobiles
d) Waste-to-energy technologies

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Ans: d) Waste-to-energy technologies

2017 Prelims PYQs

1] Consider the following pairs: [2017]

Commonly used / consumed materials and Unwanted or controversial chemicals likely to be found in them
1. Lipstick – Lead
2. Soft drinks – Brominated vegetable oils
3. Chinese fast food – Monosodium glutamate

Which of the pairs given above is/are correctly matched?
a) 1 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3

Show Answer

Ans: d) 1, 2 and 3

2015 Prelims PYQs

1] With reference to ‘fuel cells’ in which hydrogen-rich fuel and oxygen are used to generate electricity, consider the following statements: [2015]

1. If pure hydrogen is used as a fuel, the fuel cell emits heat and water as by-products.
2. Fuel cells can be used for powering buildings and not for small devices like laptop computers.
3. Fuel cells produce electricity in the form of Alternating Current (AC).

Which of the statements given above is / are correct?
a) 1 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3

Show Answer

Ans: a) 1 only

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2014 Prelims PYQs

1] Which of the following is/are the example/examples of chemical change? [2014]

1. Crystallization of sodium chloride
2. Melting of ice
3. Souring of milk

Select the correct answer using the code given below.
a) 1 and 2 only
b) 3 only
c) 1, 2 and 3
d) None

Show Answer

Ans: b) 3 only

2013 Prelims PYQs

1] Fruits stored in cold chamber exhibit long storage life because ___: [2013]

a) Exposure to sunlight is prevented
b) Concentration of Carbon dioxide in the environment is increased
c) Rate of respiration is decreased
d) There is an increase in humidity

Show Answer

Ans: c) Rate of respiration is decreased

2012 Prelims PYQs

1] What is the role of ultraviolet (UV) radiation in the water purification systems? [2012]

1. It inactivates/kills the harmful microorganisms in water.
2. It removes all the undesirable odours from the water.
3. It quickens the sedimentation of solid particles, removes turbidity and improves the clarity of water.

Which of the statements given above is/are correct?
a) 1 Only                             b) 2 & 3 Only
c) 1 & 3 Only                      d) 1,2 & 3

Show Answer

Ans: a) 1 Only   

2011 Prelims PYQs

1] Aspartame is an artificial sweetener sold in the market. It consist of amino acids and provides calories like other amino acids. Yet, it is used as a low-calorie sweetening agent in food items. What is the basis of this use? [2011]

a) Aspartame is as sweet as table sugar, but unlike table sugar, it is not readily oxidized in human body due to lack of requisite enzymes.
b) When aspartame is used in food processing, the sweet taste remains, but it becomes resistant to oxidation.
c) Aspartame is as sweet as sugar, but after ingestion into the body, it is converted into metabolites that yield no
calories.
d) Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation.

Show Answer

Ans: d) Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation.

2010-1995 Prelims PYQs

UPSC Prelims PYQ Book
  • Collection of more than 3200 Previous Year Questions (1995-2023)
  • All questions divided into 10 Subjects
  • Subject further sub-divided into more than 75 topics
  • All answers according to official answer key
  • BEST PYQ CLASSIFICATION EVER !
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