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Chemistry Past Questions

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16
A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by
  • A. boiling the water
  • B. adding excess calcium hydroxide
  • C. adding a calculated amount of calcium hydroxide
  • D. adding sodium carbonate
  • E. adding magnesium hydroxide
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17
During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment,
  • A. the litmus turns blue but no gas is evolved
  • B. the litmus turns blue and oxygen is evolved
  • C. the litmus turns blue and hydrogen is evolved
  • D. the litmus turns red and oxygen is evolved
  • E. the litmus turns red and then becomes colourless
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18
The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;
  • A. saponification
  • B. dehydration
  • C. esterification
  • D. hydrolysis
  • E. hydration
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19

The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively;

  • A. acetic acid and ethene
  • B. ethanoic acid and ethene
  • C. methanoic acid and ethylene
  • D. ethanol and ethene
  • E. acetic acid and ethylene
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20
If 30cm3 of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm3 of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively?
  • A. 9.3 sec
  • B. 14 sec
  • C. 21 sec
  • D. 28 sec
  • E. 30.3 sec
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