Chemistry Past Questions

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A small quantity of solid ammonium chloride (NH4Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone
  • A. distillation
  • B. sublimation
  • C. precipitation
  • D. evaporation
  • E. decomposition
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Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,
  • A. P will form an electrovalent bond with R
  • B. Q will form a covalent bond with S
  • C. R will form an electrovalent bond with S
  • D. Q will form an electrovalent bond with S
  • E. Q will form a covalent bond with R
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An element X forms the following compounds with chlorine; XCl4, XCl3, XCl2. This illustrates the
  • A. law of multiple proportions
  • B. law of chemical proportions
  • C. law of simple proportions
  • D. law of conservation of mass
  • E. law of definite proportions
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The oxidation state of chlorine in potassium chlorate is
  • A. +1
  • B. +2
  • C. +3
  • D. +5
  • E. +7
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When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;
  • A. nitrogen and carbondioxide
  • B. the rare gases
  • C. nitrogen and oxygen
  • D. nitrogen and the rare gases
  • E. nitrogen, carbondioxide and the rare gases
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