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Tuesday, 19 May 2026
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Chemistry Past Questions and Answers

Chemistry Questions

Question 411:
A man suspected of being drunk is made to pass his breath into acidified potassium dichlormate solution. If his breath carries a significant level of ethanol, the final colour of the solution is?
  • A Pink
  • B Purple
  • C Orange
  • D Blue-black
  • E Green
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Question 412:
When pollen grains are suspended in water and viewed through a microscope, they appear to be in a state of constant but erratic motion. This is due to?
  • A Convection currents
  • B Small changes
  • C Small changes in temperature
  • D A chemical reaction between the pollen grain and water
  • E The bombardment of the pollen grains by molecules of water
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Question 413:
The energy change (ΔH) for the reaction CO(g) + (1)/(2)O<sub style='font-size: smaller;'>2(g)</sub> → is?<br/>(ΔHi(CO) = -110.4 kJ mol<sup style='font-size: smaller;'>-</sup>) (ΔHi(CO<sub style='font-size: smaller;'>2</sub>) = -393 kJ mol<sup style='font-size: smaller;'>-</sup>)
  • A -503.7 kJ
  • B +503.7kJ
  • C -282.9 kJ
  • D +282.9 kJ
  • E +393.3 kJ
View Answer & Explanation
Question 414:
Tetraoxosulphate (IV) ions are finally tested using?
  • A Acidified silver nitrate
  • B Acidified barium chloride
  • C Ime-water
  • D Dilute hydrochloric acid
  • E Acidified lead nitrate
View Answer & Explanation
Question 415:
An organic compound decolourized acidified KMnO<sub style='font-size: smaller;'>4</sub> solution but failed to react with ammoniacal silver nitrate solution. The organic compound is likely to be?
  • A A carbonxylic acid
  • B An alkane
  • C An alkene
  • D An alkyne
  • E An akanone
View Answer & Explanation