GK in English

GK Chapterwise – CDS Previous Year Papers

Table of Contents

21. What is the Jeweller’s rouge?

(a)Ferric oxide
(b) Ferrous oxide
(c) Ferrous carbonate
(d) Ferric carbonate
Ans: (a)
CDS Exam (II) 2007

22. Which one of the following is used in the preparation of antiseptic solution?

(a)Potassium nitrate
(b) Iodine
(c) Iodine chloride
(d) Potassium chloride
Ans: (b)
CDS Exam (I) 2009

23. Which of the following has maximum density?

(a)Chloroform
(b) Water
(c) Benzene
(d) Ice
Ans: (b)

CDS (I) 2018

24. Which one of the following properties changes with valency?

(a)Atomic weight
(b) Equivalent weight
(c) Molecular weight
(d) Density
Ans: (b)

CDS (II) 2016

25. Which one of the following is the softest?

(a)Sodium
(b) Aluminium
(c) Iron
(d) Copper
Ans: (a)
CDS Exam (II) 2008

26. Which one of the following is correct? Butter is

(a)a supercooled oil
(b) an emulsion
(c) a molecular solid
(d) None of these
Ans: (d)

CDS (II) 2010

27. The rusting of iron nail

(a)decreases its weight
(b) increases its weight
(c) does not affect weight but iron is oxidised
(d) does not affect weight but iron is reduced
Ans: (b)

CDS (I) 2015

28. Which one of the following is correct? Setting of plaster of Paris is

(a)dehydration
(b) oxidation with atmospheric oxygen
(c) hydration leading to another hydrate
(d) combination with atmospheric C02 31. Which one of the following is heavy water used in nuclear reactor?
(a)Water having molecular weight 18 u
(b) Water having molecular weight 20 u
(c) Water at 4°C but having molecular weight 19 u
(d) Water below the ice in a frozen sea
Ans: (c)

CDS (II) 2011

29. Which one of the following is the secondary source of light in a fluorescent lamp?

(a)Neon gas
(b) Argon gas
(c) Mercury vapour
(d) Fluorescent coating
Ans: (d)
CDS Exam (II) 2013

30. Statement I: Addition of water to an aqueous solution of HC1 decreases the pH. Statement II: Addition of water suppresses the ionisation of HC1.

(a)Both the statements are individually true and Statement II is the correct explanation of Statement I
(b) Both the statements are individually 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: (c)

CDS (II) 2017

31. Which one of the following is not a chemical change?

(a)Burning of coal in air
(b) Fermentation of sugar cane juice
(c) Crystallisation of table salt from sea water
(d) Cracking of petroleum
Ans: (c)

CDS (I) 2015

32. Statement I: Soaps do not form lather with water containing salts of calcium and magnesium. Statement II: Calcium and magnesium salts of long chain fatty acids are insoluble in water.

(a)Both the statements are individually true and Statement II is the correct explanation of Statement I.
(b) Both the statements are individually 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) 2019

33. Nail polish remover contains

(a)acetone
(b) benzene
(c) formaldehyde
(d) acetic acid
Ans: (a)
CDS Exam (II) 2012

34. Aqua-regia used by alchemists to separate silver and gold is a mixture of

(a)hydrochloric acid (concentrated) and nitric acid
(concentrated)
(b) hydrochloric acid (concentrated) and sulphuric acid (concentrated)
(c) nitric acid (concentrated) and sulphuric acid
(concentrated)
(d) hydrochloric acid (dilute) and sulphuric acid (dilute)
Ans: (a)

CDS (II) 2007

35. Commercial vulcanisation of rubber involves

(a)sulphur
(b) carbon
(c) phosphorus
(d) selenium
Ans: (d)

CDS (I) 2009

36. Which one of the following when dissolved in H2O gives hissing sound?

(a)Limestone
(b) Slaked lime
(c) Sodalime
(d) Quicklime
Ans: (b)
CDS Exam (I) 2018

37. The light emitted by firefly is due to

(a)a radioactive substance
(b) chemiluminiscence process
(c) a photoelectric process
(d) burning of phosphorus
Ans: (a)
CDS Exam (II) 2016

38. Which of the following statements about the commonly used automobile battery are true?
I. It is usually a lead-acid battery.
II. It has six cells with a potential of 2 V each.
III. Its cells work as galvanic cells while discharging power.
IV. Its cells work as electrolytic cells while recharging.
Select the correct answer using the codes given below

(a)I, II, III and IV
(b) I, II and III
(c) II and IV
(d) III and IV
Ans: (d)

CDS (II) 2008

39. Which one of the following is used as a mordant in dyeing and tanning industry?

(a)Magnesium oxide
(b) Magnesium carbonate
(c) Magnesium chloride
(d) Magnesium sulphate
Ans: (c)

CDS (I) 2010

40. Which one of the following petroleum refinery products has the lowest boiling point?

(a)Kerosene
(b) Diesel
(c) Gasoline
(d) Lubricating oil
Ans: (b)
CDS Exam (I) 2015

DsGuruJi Homepage Click Here