NDA CHEMISTRY PAST QUESTION ’15’

Check NDA Chemistry past questions and answers for 1 – 20 here

21. Calculate the mass of solute in 50cm3 of 0.25mnm-3 sodium trioxocarbonate (IV)
(Na = 23, C= 12, O = 16).
A. 1.325g
B. 5.30g
C. 0.27g
D. 3.0g

22. Sulphur oxide is prepared by the action of cone H2SO4 on copper. The gas SO2produced is moist and is dried by passing the gas_____
A. Over dilute HCl
B. Over CaO
C. Over Concentrated H2SO4
D. Under Concentrated HNO3

23. Select the equation representing the action of steam on red hot iron.
A. Fe + H2O ⟶ FeO + H2
B. 2Fe + 3H2O ⟶ FeSO3 + H2
C. 3Fe + 4H2O ⟶ Fe(OH)3 + H2
D. 3Fe + 4H2O ⟶ Fe3O4 + 4H2O

24. Nitrogen is very uncreative because
A. Much energy is needed to break the bond between the two Nitrogen atoms in the molecules
B. Less energy is needed to break the bond between the two Nitrogen atoms in the molecules
C. Of the electrovalent bond between the two atoms
D. Of the covalent bond between the two atoms.

25. Calculate the mass of trioxonitrate (V) acid necessary to react with 10g of Lead Oxide and the mass of Lead trioxonitrate (V) salt formed in the (Pb = 207, N = 14, O = 16, H = 1)
A. 6.55g
B. 5.65g
C. 14.8g
D. 0.565g

26. X has an empirical formula C2H5, and relative molecular mass 58. X is
A. Ethane
B. Propane
C. Butane
D. Hexane

27. The cracking of petroleum increases the yield of gasoline because it converts
A. Higher alkalis into lower alkanes and gasoline
B. Lower Alkanes and alkenes into higher alkenes
C. Alkenes into alkenes by hydrogenation
D. Alkenes into alkanol by hydration

28. what is the pH of 0.01 M hydrochloric acid solution?
A 2
B. 3
C. 6
D. 5

29. Aqua-regia is a mixture of_____
A. One part of conc. HNO2 and one part of conc. HCl
B. Three parts of conc. HNO3 and one part of conc. HCl
C. Two parts of conc. HNO3 and one part of conc. HCl
D. Two parts of conc. HNO3 and three part of conc. HCl

30. Graphite conducts electricity because?
A. it is crystalline
B. it contains an excess of electrons
C. contains an excess of electrons
D. its atoms are close together

31. Which of the following compounds is composed of Al, Si, O and H?
A. Epsom salt
B. Limestone
C. Clay
D. Urea

32. The nucleus of an atom consists of
A. electrons and neutrons
B. electrons and protons
C. proton and neutrons
D. All of the above

33. What is the advantage of an alloying lead with tin?
A. melting point is increased
B. workability is reduced
C. the alloy is used in joining metals
D. the alloy is a catalyst in iron on extraction

34. Which of the following statement is correct about Osmotic Pressure
A. It is the pressure required to prevent a solute flowing across a semi-permeable membrane from high to low region of concentration.
B. It is the pressure required to allow a solvent flowing across a semi-permeable membrane from high to low region of concentration.
C. It is the pressure required to prevent a solvent flowing across a semi-permeable membrane from a region of high to low region of concentration.
D. It is the pressure required to prevent a solvent flowing across a semi-permeable membrane from a region of low to a high region of concentration.

35. In the Haber process for the manufacture of ammonium, the catalyst commonly used is finely divided
A. vanadium
B. platinum
C. iron
D. copper

36. A mixture of sand, ammonium chloride and sodium is best separated by
A. sublimation followed by addition of water and filtration
B. sublimation followed by addition of water and evaporation
C. addition of water followed by filtration and sublimation
D. addition of water followed by crystallization and sublimation

37. The densities of two gases, X and Y, are 0.5g dm3 and 2.0g dm-3 respectively. What is the rate of diffusion of X relative to Y?
A. 0.1
B. 0.5
C. 2.0
D. 4.0

38. The number of electrons in the valence shell of an element of atomic number 14 is
A. 1
B. 2
C. 3
D. 4

39. A solid that absorbs water from the atmosphere and forms an aqueous solution is
A. hydrophilic
B. efflorescent
C. deliquescent
D. hygroscopic

40. How many moles of HCl will be required to react with potassium heptaoxodichromate (VI) to produce 3 moles of chlorine?
A. 14
B.12
C. 11
D. 10

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