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Chemistry Past Questions and Answers

Jamb Chemistry Questions

Question 71:
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
View Answer & Explanation
Question 72:
The derivative of benzene that can be used in making explosives is
  • A Aniline
  • B Xylene
  • C Phenol
  • D Toluene
View Answer & Explanation
Question 73:
In electrovalency, the oxidation number of the participating metal is always
  • A Decreasing
  • B Increasing
  • C Constant
  • D Neutral
View Answer & Explanation
Question 74:
The ionic radii of metals are usually
  • A Greater than their atomic radii
  • B Unaffected by the charge on the ion
  • C The same as their atomic radii
  • D Less than their atomic radii
View Answer & Explanation
Question 75:
Calculate the percentage composition of oxygen in calcium trioxocarbonate(IV) [Ca=40, C=12, O=16]
  • A 16
  • B 48
  • C 40
  • D 12
View Answer & Explanation