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Saturday, 03 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 1:
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
View Answer & Explanation
Question 2:
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
View Answer & Explanation
Question 3:
20 cm3 of 1 M H\(_2\)SO\(_4\) is mixed 20 cm\(^3\) of 1 M NaOH. The resulting solution is?
  • A Acidic with a molarity of 0.50 M H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>
  • B Acidic with a molarity of 0.25 H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>
  • C Neutral
  • D Alkaline with a molarity of 0.25 M NaOH
  • E Alkaline with a molarity of 0.50 M NaOH
View Answer & Explanation
Question 4:
A cold aqueous solution of sodium chloride is electrolyzed using a graphite anode and an iron cathode. In the course of the electrolysis the electrolyte is continuously stirred. The liquid left after electrolysis will therefore consist of?
  • A Sodium hydroxide solution
  • B Chlorine water
  • C Pure water
  • D Sodium hypochlorite solution
  • E Hydrochloric acid solution
View Answer & Explanation
Question 5:
Which of the following statements is correct during the electrolysis of a caustic soda solution using platinum electrodes?
  • A Oxygen gas is given off at the cathode
  • B Hydrogen gas is given of at the anode
  • C Sodium metals is deposited at the anode
  • D Sodium metal is deposited at the cathode
  • E AAlkalinity at the cathode increases
View Answer & Explanation