NDA CHEMISTRY PAST QUESTION ’12’

Check questions 1 – 20 here

21. The solubility of solids increases with an increase in the temperature of solvent. Which of the following salts has its solubility unaffected with a rise in temperature?
A.   KNO3
B.   KI
C.   KCl
D.   NaCl

22. In the contact process for the manufacture of sulphuric acid, sulphur trioxide gas is not passed directly in water because:
A. It is not much soluble in water
B. It does not form sulphuric acid with water
C. Colloidal sulphur is deposited
D. A mist of fine chops of dilute sulphuric acid fill the pipes if direct adsorption in water is tried

23. Cu(s) + HNO3(l) → Cu(NO3)2(l) +H20(l) + 2NO2(g) in the above reaction, nitric acid is acting as:
A. an oxidizing agent
B. a reducing agent
C. a nitrating agent
D. a hydrating agent

24. Which of the following salt is used in the preparation of caustic soda, washing soda, hydrochloric acid, bleaching powder etc?
A. NaNO3
B. Na2O
C. NaSO4
D. NaCl

25. Ammonia is used as a commercial refrigerant because:
A. it is a non-polar compound
B. the gas is very cheap
C. it is very soluble in water
D. it is easily liquefied and when allowed to evaporate, absorbs large, quantities of heat producing low temperature

26.If a salt is dissolved in water and the resulting solutions feels cold to the hand. This implies that it is:
A. Thermostatic
B. Thermophilic
C. Exothermic
D. Endothermic

27. Which of the following statements is corrects 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 concentration
D. It is the pressure required to prevent a solvent flowing across a semi-permeable membrane from a region or low to high to concentration

28. The heat change associated with a given chemical change is always constant and is independent of time and of any intermediate changes involved. This is
A. Dalton’s Law of Heat Summation
B. Hess’s Law of Heat Summation
C. Dulon & Petil Law of Heat Summation
D. Born-Haber Law of Heat Summation

29. Electrovalency is best favoured by:
A. a large metallic atom and a small non-metallic atom
B. a small stable atom
C. a large anion which loses electrons
D. resonance in the bonding pairs

30. Which of the following better defines a black body?
A. A perfect absorber of energy and retains any radiant energy
B. A perfect absorber of transmitted energy
C. A perfect absorber of monochromatic light
D. A perfect absorber of quantised energy

31. What is the advantage of 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 are extraction

32. Which of these ions gives a dark green precipitate with sodium hydroxide solution but a dark blue precipitate with potassium hexacyanoferrate (ii) Solution?
A. Fe3+
B. Fe2+
C. Pb2+
D. Sn2+

33. What is the effect of addition of a catalyst on a reversible reaction in a dynamic equilibrium?
A. shifts the equilibrium to the right
B. shifts the equilibrium to the left
C. does not affect the equilibrium position
D. increase the equilibrium constant

34. Which of these statements is true?
A. A base is always soluble in water
B. Sodium hydroxide is both a base and an alkali
C. Hydrogen is released whenever an acid and metal are mixed
D. A gardener neutralizes an alkaline soil by the addition of lime

35. When the trixonitrate (v) salt of an alkali metal M is heated. the formula of the solid product formed is ___.
A. M2O3
B. MnO
C. MO2
D. MnO2

36. Chromatograph is used to separate components of mixtures which differ in their rates of ___.
A. diffusion
B. migration
C. reaction
D. sedimentation

37. The number of hydrogen ions in 4.8g of tetraoxosulphate (V) acid is
A. 3.01 x 1022
B. 6.02 x 1023
C. 3.01 x 1023
D. 6.02 x 1023
[S= 32, O= 16, H=1] Na = 6.02 x 1023]

38. Which of the following tests will completely identify any one of sulphur (IV) oxide, hydrogen, carbon (IV) oxide and nitrogen (II) oxide?
A. pass each gas into water and test with blue litmus paper
B. pass each gas into lime water
C. expose each gas to atmosphere air
D. pass each gas into concentrated tetraoxosulphate (VI) acid

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

40. A metallic oxide which reacts with both HCl and NaOH to give salt and water only can be classified as ___.
A. an acidic oxide
B. a basic oxide
C. a neutral oxide
D. an amphoteric oxide

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