A thousand ways to pass basic chemistry examination

41.An element which exists in more than one crystalline form is said to exhibit
  • A. Polymorphism
  • B. isotopy
  • C. allotropy
  • D. isomerism
42.A mixture of starch solution and potassium oxide was placed in a test tube. On adding dilute tetraoxosulphate (VI) acid then K₂Cr₂O₇ solutions, a blue-black colour was produced. In this reaction, the
  • A. iodide is oxidized
  • B. tetraoxosulphate (VI) acid acts as an oxidizing agent
  • C. starch has been oxidized.
  • D. K₂CrcO₇ is oxidized.
43.Which of the following statements is true?
  • A. The heat of solution of NaOH is positive?
  • B. The NaOH gains heat from the surrounding
  • C. The heat of solution of NaOH is negative.
  • D. The dissolution of NaOH in water is endothermic
44.Which property of a reversible reaction is affected by a catalyst?
  • A. Heat content (enthalpy)
  • B. energy activation
  • C. free energy change
  • D. equilibrium position
45.Which of the following is used in fire extinguishers?
  • A. Carbon (ii) oxide
  • B. carbon (iv) oxide
  • C. sulphur (iv) oxide
  • D. ammonia
46.When H₂S gas is passed into a solution of iron (iii) chloride, the colour changes from yellow to green. This is because
  • A. H₂S is reduced to S
  • B. Fe³⁺ ions are oxidized by H₂S
  • C. Fe³⁺ ions are oxidized by Fe²⁺ ions
  • D. Fe³+ ions are reduced to Fe²⁺ ions.
47.Suitable reagents for the laboratory preparation of nitrogen are ___.
  • A. sodium dioxonitrate (III) and ammonium chloride
  • B. sodium trioxonitrate (V) and ammonium chloride
  • C. sodium chloride and ammonium trioxonitrate (V)
  • D. sodium chloride and ammonium diozonitrate
48.The thermal decomposition of copper (II) trioxonitrate (V) yields copper (II) oxide, oxygen and ___
  • A. nitrogen (II) oxide
  • B. nitrogen (I) oxide
  • C. nitrogen (IV) oxide
  • D. nitrogen.
49.Which of the following is an example of a chemical change?
  • A. freezing of water
  • B. dissolution of NaCl
  • C. rusting of iron
  • D. separation a liquid mixture by distillation.
50.The electronic configuration in the ground state of the chloride ion (Cl⁻) is
  • A. 1s² 2s² 2p⁶ 3s² 3p⁵
  • B. 1s² 2s² 2p⁶ 3s² 3p⁶
  • C. 1s² 2s² 2p⁶ 3s² 3p⁷
  • D. 1s² 2s² 2p⁶ 3s² 3p⁷
51.Which of the following is not a member of the homologous series of paraffins (alkanes)?
  • A. C₃H₆
  • B. C₅H₁₂
  • C. C₇H₁₆
  • D. C₂₄H₄₈
52.Which of the following statement is an exception in the assumptions of the kinetic theory of gases?
  • A. The particles are of negligible size
  • B. The particles are in constant random motion
  • C. The particles are of negligible mass
  • D. The particles collide with each other.
53.An example of alcohol is
  • A. CCl₄
  • B. CH₃COOH
  • C. CHCl₃
  • D. CH₃OH
54.Hypochlorous acid is used as a bleach because
  • A. It is a strong acid
  • B. It yields chlorine readily in pure water
  • C. It is an oxidizing agent
  • D. It is a weak acid
55.Which of the following compounds will form a solution if exposed to air?
  • A. Na₂CO₃.10H₂O
  • B. NaNO₃
  • C. CuSO₄
  • D. CaCl₂
56.Consider the following exothermic reaction 2SO₂(g) + O₂(g) <----> 2SO₃(g) If the temperature of the reaction is reduced from 8000C to 5000C, and no other change takes place, then
  • A. the reaction rate increases
  • B. concentration of SO₃ decreases
  • C. concentration of SO₃ increases
  • D. O₃ gas becomes unreactive
57.Alkanoates are formed by the reaction of alkanoic acid with ___.
  • A. alkyl halides
  • B. alkanols
  • C. ethers
  • D. sodium
58.Methylethanoate reacts with ammonia to yield __
  • A. methylamine and ethanol
  • B. ethylamine methanol
  • C. methanamide and ethanol
  • D. ethanamide and methanol
59.Crude copper can be purified by the electrolysis of CuSO4 if
  • A. Platinum electrodes are used
  • B. The crude copper is made the anode of the cell
  • C. The crude copper is made the cathode of the cell
  • D. Crude copper are used.
60.Aluminium is extracted commercially from its ore by
  • A. Heating aluminium oxide with coke in a furnace
  • B. The electrolysis of fused aluminium oxide in cryolite
  • C. Treating cryolite with sodium hydroxide solution under pressure.
  • D. Heating sodium aluminium silicate to a high temperature