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Sunday, 04 October 2026
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Chemistry Past Questions and Answers

Topic: Dilute and concentrated NaCl solutions

Jamb Chemistry Questions - Dilute and concentrated NaCl solutions

Question 21:
Three drops of a 1.0 mol dm-3 solution of NaOH are added to 20 cm3 of a solution of pH 8.4. The pH of the resulting solution will be
  • A Close to that of pure water
  • B Unaltered
  • C Greater than 8.4
  • D Less than 8.4
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Question 22:
Which of the following gives a precipitate when treated with NaOH solution?
  • A AlCl<sub style='font-size: smaller;'>3</sub>
  • B NH<sub style='font-size: smaller;'>4</sub>CL
  • C CH<sub style='font-size: smaller;'>3</sub>COONa
  • D Na<sub style='font-size: smaller;'>2</sub>CO<sub style='font-size: smaller;'>3</sub>
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Question 23:
In the electrolysis of a concentrated solution of sodium chloride using electrodes, which of the following ions are discharged at the cathode and anode respectively?
  • A Na<sup style='font-size: smaller;'>+</sup> and Cl<sup style='font-size: smaller;'>-</sup>
  • B Na<sup style='font-size: smaller;'>+</sup> and OH<sup style='font-size: smaller;'>-</sup>
  • C H<sup style='font-size: smaller;'>+</sup> and OH<sup style='font-size: smaller;'>-</sup>
  • D H<sup style='font-size: smaller;'>+</sup> and Cl<sup style='font-size: smaller;'>-</sup>
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Question 24:
Hydrogen can be displaced from a hot alkaline solution by
  • A Fe
  • B Cu
  • C Ca
  • D Sn
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Question 25:
The ion that will give a white precipitate with aqueous NaOH and soluble in excess of the base is
  • A Ca<sup style='font-size: smaller;'>2+</sup>
  • B Mg<sup style='font-size: smaller;'>2+</sup>
  • C Zn<sup style='font-size: smaller;'>2+</sup>
  • D Cu<sup style='font-size: smaller;'>2+</sup>
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