NDA CHEMISTRY PAST QUESTION ’16’

Check NDA Chemistry question 1 – 20 here

21. Which of the following statements about soapless detergents is correct? They
A. lather easily with hard water
B. increase the surface tension of water
C. cause hydrolysis of salts in water
D. form a curdy precipitate with soft water

22.

 

In this reaction above, x and y are:
A. 234 and 91
B. 235 and 90
C. 233 and 89
D. 230 and 86

23. Cancerous growths are Cured by exposure to
A. α-rays
B. χ-rays
C. γ-rays
D. β-rays

24. When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes
A. bipolar
B. Negatively charged
C. Positively charged
D. Neutral

25. Nuclear fission involves the slipping of a heavy element into two nuclei of
A. equal masses with a release of energy
B. nearly equal masses with a release of energy and radiation
C. equal masses with a release of energy and radiation
D. unequal masses without any release of energy

26.

 

 

 

 

 

The graph above demonstrates the effect of
A. pressure on the rate of reaction
B. concentration on the rate of reaction
C. surface area on the rate of reaction
D. catalyst on the rate of reaction

27. The electronic configuration of Mg2+ is
A. 1s22s22p63s23p2
B. 1s22s22p63s2
C. 1s22s22p6
D. 1s22s22p4

28. The minimum amount of energy required for a reaction to take place is
A. Activation energy
B. kinetic energy
C. Lattice energy
D. Ionization energy

29. A 50.0mg supply of iodine -131, used in hospital in the treatment of hyperthyroidism was stored for 32.4 days. If the half-life of iodine – 131 is 8.1 days, how many milligrams remain?
A. 3.125mg
B. 13.60mg
C. 13.13mg
D. None of the above

30. Radioactive changes differ from ordinary chemical changes in that radioactive changes
A. are explosive
B. absorb energy
C. release energy
D. involve changes in the nucleus

31. The addition of water to calcium oxide leads to
A. a physical change
B. a chemical change
C. the formation of a mixture
D. an endothermic change

32. A colourless solution was tested with Tollen’s reagent, the colourless solution gave a silver mirror. This indicates the presence of
A. Carboxylic acid
B. Ketone
C. Amine
D. Aldehyde

33. The metal used to recover copper from a solution of copper sulphate is
A. Na
B. Ag
C. Hg
D. Fe

34. The Metallurgical process in which a metal is obtained in a fused stare is called
A. smelting
B. roasting
C. calcinations
D. froth floatation

35. Which of the following statements is correct? Aqueous solution of oxides of group 1 elements Li, Na, K etc. are:
A. Acidic to litmus
B. Amphoteric
C. Basic to litmus
D. Neutral to litmus

36. Which of the following is not true about electrovalent compounds.
A. They do not contain molecules
B. The electrical forces between the oppositely charged ions art powerful
C. They are rarely soluble in organic liquids
D. They are not soluble in water

37. The reaction of an alkene with hydrogen in the presence of a catalyst is
A. a nucleophilic reaction
B. an addition reaction
C. a substitution reaction
D. an oxidative reaction

38. The substance least considered as a source of environmental pollution is
A. uranium
B. lead compound
C. Organophosphorous compounds
D. silicate minerals.

39. In the reaction CaC2(s) + 2H2O ⟶ Ca(OH)2(s) + C2H2(g), what is the mass of solid calcium needed to produce 1000cm3 acetylene gas at S.T.P?
[ C=2, Ca= 40, G.M.N =22400cm3]
A. 3.8g
B. 2.9g
C. 2.0g
D. 1.0g

40. If “d” represents the density of a gas and “k” is a constant, the rate of gaseous diffusion “r” is directly related to d by the equation:
A. r = kOd
B. r1 = kd
C. r = kd
D. r = 1/kd

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