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Chemistry Past Questions and Answers

Chemistry Questions

Question 631:
JAMB 1990
Iron galvanized with zinc is cathodically protected from corrosion. This is because?
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  • A Zinc has a more positive oxidation potential than iron
  • B Zinc has less positive oxidation potential than iron
  • C Bith have the same oxidation potential
  • D Zinc is harder than iron
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Question 632:
JAMB 1990
Which of the following samples will react fastest with dilute trioxonitrate (V) acid?
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  • A 5 g of lumps of CacO<sub style='font-size: smaller;'>3</sub> at 25°C
  • B 5 g of powered CacO<sub style='font-size: smaller;'>3</sub> at 25°
  • C 5 g of lumps of CaCO<sub style='font-size: smaller;'>3</sub> at 50°C
  • D 5 g of powered CaCO<sub style='font-size: smaller;'>3</sub> AT 50°C
View Answer & Explanation
Question 633:
JAMB 1990
In the reaction:<br/>2Hl<sub style='font-size: smaller;'>(g)</sub> ↔ H<sub style='font-size: smaller;'>2(g)</sub> + l<sub style='font-size: smaller;'>2(g)'</sub> ΔH = 10 kj;<br/>The concentration of iodine in the equilibrium mixture can be increased by?
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  • A Raising the pressure
  • B Raising the temperature
  • C Adding a catalyst
  • D Lowering the pressure
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Question 634:
JAMB 1990
Which of the following gases can be collected by the upward displacement of air?
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  • A NO
  • B H <sub style='font-size: smaller;'>2</sub>
  • C NH<sub style='font-size: smaller;'>3</sub>
  • D Cl <sub style='font-size: smaller;'>2</sub>
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Question 635:
JAMB 1990
The brown fumes given off when trioxonitrate (V) acid is heated consist of ?
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  • A NO<sub style='font-size: smaller;'>2</sub> and O<sub style='font-size: smaller;'>2</sub>
  • B H<sub style='font-size: smaller;'>2</sub>O and NO<sub style='font-size: smaller;'>2</sub>
  • C NO<sub style='font-size: smaller;'>2'</sub> O<sub style='font-size: smaller;'>2</sub> and H<sub style='font-size: smaller;'>2</sub>O
  • D NO, NO<sub style='font-size: smaller;'>2</sub> and H<sub style='font-size: smaller;'>2</sub>O
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