ICSE Class 10 Chemistry: Electrolysis — Important Questions with Answers 2026

Short Answer Questions (2-3 Marks)

• Q: Define electrolysis. What are electrolytes and non-electrolytes?
  Ans: Electrolysis is the chemical decomposition of an electrolyte by passing electric current through it. Electrolytes: substances that conduct electricity in molten or aqueous state due to presence of free ions. Example: NaCl, CuSO₄. Non-electrolytes: substances that do not conduct electricity. Example: sugar, urea.
• Q: Explain the electrolysis of acidified water. What is collected at each electrode?
  Ans: Acidified water (H₂SO₄ added as electrolyte): At cathode (−): 4H⁺ + 4e⁻ → 2H₂↑ (hydrogen gas collected). At anode (+): 4OH⁻ → 2H₂O + O₂↑ + 4e⁻ (oxygen gas collected). Volume ratio: H₂:O₂ = 2:1. Test: H₂ burns with a pop sound, O₂ relights a glowing splint.
• Q: Explain electroplating of a spoon with silver.
  Ans: Electrolyte: Silver nitrate (AgNO₃) solution. Cathode: Spoon (object to be plated). Anode: Pure silver rod. At cathode: Ag⁺ + e⁻ → Ag (silver deposits on spoon). At anode: Ag → Ag⁺ + e⁻ (silver dissolves to replenish solution). Purpose: decoration, corrosion prevention, durability.

Long Answer / Application Questions (4-6 Marks)

• Q: State Faraday's First Law of Electrolysis.
  Ans: Faraday's First Law states: The mass of a substance deposited or liberated at an electrode during electrolysis is directly proportional to the quantity of electricity (charge) passed through the electrolyte. m = ZIt, where Z is the electrochemical equivalent, I is current, t is time.
• Q: During electrolysis of CuSO₄ using copper electrodes, what happens at each electrode?
  Ans: At cathode (−): Cu²⁺ + 2e⁻ → Cu (copper deposits — cathode gains mass). At anode (+): Cu → Cu²⁺ + 2e⁻ (copper dissolves — anode loses mass). The concentration of CuSO₄ solution remains constant because copper dissolved at anode replaces copper deposited at cathode.

Exam Tips for This Chapter

• Revise all definitions and laws from Electrolysis — they are commonly asked as 1-2 mark questions
• Practice diagrams related to Electrolysis — neat labelled diagrams carry 2-3 marks
• For numericals, always show formula → substitution → answer with correct units
• Previous year analysis shows Electrolysis carries 8-12 marks in the board exam