GK in English

GK Chapterwise – CDS Previous Year Papers

Table of Contents

81. Which one among the following nontoxic gases helps in formation of enzymes which ripen fruit?

(b) Ethane
(c) Methane
(d) Carbon dioxide
Ans: (a)

CDS (I) 2015

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

(a)C-12 and C-13
(b) C-13 and C-14
(c) C-12 and C-14
(d) C-12 and carbon black
Ans: (c)

CDS (II) 2019

83. What is the main constituent of a pearl?

(a)Calcium carbonate and magnesium carbonate
(b) Calcium sulphate only
(c) Calcium oxide and calcium sulphate
(d) Calcium carbonate only
Ans: (d)
CDS Exam (II) 2012

84. From which one among the following water sources, the water is likely to be contaminated with fluoride?

(a)Ground water
(b) River water
(c) Pond water
(d) Rain water
Ans: (a)

CDS (II) 2007

85. The pH of fresh ground water slightly decreases upon exposure to air because

(a)carbon dioxide from air is dissolved in the water
(b) oxygen from air is dissolved in the water
(c) the dissolved carbon dioxide of the ground water escapes into air
(d) the dissolved oxygen of the ground water escapes into air
Ans: (a)

CDS (I) 2009

86. Which one among the following statements is correct?

(a)All bases are alkalis
(b) None of the bases is alkali
(c) There are no more bases except the alkalis
(d) All alkalis are bases but all bases are not alkalis
Ans: (d)

CDS (II) 2018

87. Which one among the following statements about an atom is not correct?

(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
Ans: (d)

CDS (II) 2008

88. The macro nutrients provided by inorganic fertilizer are

(a)carbon, iron and boron
(b) magnesium, manganese and sulphur
(c) magnesium, zinc and iron
(d) nitrogen, phosphorus and potassium
Ans: (b)

CDS (I) 2010

89. Statement I: All compounds contain more than one element.
Statement II: All compounds are heterogeneous mixtures.

(a)Both the statements are true and statement II is the correct explanation of statement I
(b) Both the statements are true, but statement II is not the correct explanation of statement I
(c) Statement I is true, but statement II is false
(d) Statement I is false, but statement II is true
Ans: (a)

CDS (II) 2015

90. In an atomic explosion, release of large amount of energy is due to conversion of

(a)chemical energy into nuclear energy
(b) nuclear energy into heat
(c) mass into energy
(d) chemical energy into heat
Ans: (a)
CDS Exam (II) 2011

91. Soaps cannot be used in acidic condition because they lose their cleansing effect due to formation of insoluble

(b) alcohols
(c) hydrocarbons
(d) long chain fatty acids
Ans: (d)

CDS (II) 2013

92. The elements of a group in the periodic tabic

(a)have similar chemical properties
(b) have consecutive atomic numbers
(c) are isobars
(d) are isotopes
Ans: (a)

CDS (I) 2017

93. Which one among the following polymers is used for making bulletproof material?

(a)Polyvinyl chloride
(b) Polystyrene
(c) Polyethylene
(d) Polyamide
Ans: (c)
CDS Exam (I) 2015

94. Match the following lists. List I List II
(Agent) (Disease)
A. Arsenic 1 Fluorosis
B. Fluoride 2 Melanosis
C. Dust 3 Presbycusis
D. Noise 4 Sillicosis Codes A B C D A B C D

(a)3 1 4 2
(b) 3 4 1 2
(c) 2 1 4 3
(d) 2 4 1 3
Ans: (c)
CDS Exam (II) 2019

95. Iodised salt is a

(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
Ans: (c)

CDS (II) 2012

96. Antacids are commonly used to get rid of acidity in the stomach. A commonly used antacid is

(a)sodium hydrogen phthalate
(b) magnesium hydroxide
(c) calcium hydroxide
(d) manganese acetate
Ans: (b)

CDS (I) 2007

97. On the labels of the bottles, some soft drinks are claimed to be acidity regulators. They regulate acidity using

(a)carbon dioxide
(b) bicarbonate salts
(c) Both (a) and
(d) carbon dioxide and lime
Ans: (b)
CDS Exam (I) 2009

98. The gas which turns lime water milky is

(a)carbon dioxide
(b) carbon monoxide
(c) ammonia
(d) nitrogen dioxide
Ans: (a)

CDS (I) 2018

99. Why hard water does not give lather with soap?

(a)Hard water contains calcium and magnesium ions which form precipitate with soap
(b) Hard water contains sulphate and chloride ions which form precipitate
(c) pH of hard water is high
(d) pH of hard water is less
Ans: (a)

CDS (I) 2008

100. Which one among the following metals is used in fireworks to make a brilliant white light?

(b) Magnesium
(c) Aluminium
(d) Silver
Ans: (b)
CDS Exam (I) 2010

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