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CBSE Class 8 Science Chapter 11 Chemical Effects of Electric Current Worksheet with Answers

Chemical Effects of Electric Current is a scoring chapter in CBSE Class 8 Science that introduces students to how electricity interacts with chemical solutions. This printable worksheet offers structured practice across all question types found in the CBSE board exams. Parents can print this for weekend revision, while students can use it to test their grasp of conductors, electrolysis, and electroplating before school assessments.

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Key takeaways

  • ✓Complete worksheet covering conductivity of liquids, electrolysis, and electroplating from NCERT Class 8 Science Chapter 11
  • ✓Includes 45+ questions across difficulty levels: MCQs, fill-in-the-blanks, short and long answers, plus one case-study question
  • ✓Difficulty level: Moderate; suggested time: 60 minutes for full worksheet completion
  • ✓Detailed answer key with brief explanations provided for every question to aid self-study
  • ✓Aligned with latest CBSE Class 8 Science syllabus and board exam pattern
  • ✓Tests application-level understanding through HOTS and case-based questions
  • ✓Perfect for weekly practice, revision before term exams, and concept reinforcement

Quick Chapter Recap: Chemical Effects of Electric Current

Chapter 11 explores three major themes from the NCERT Class 8 Science syllabus. First, conductivity of liquids: not all liquids conduct electricity — distilled water does not, but tap water and salt solutions do because of dissolved ions. Second, electrolysis: the process by which an electric current decomposes a chemical compound, such as water splitting into hydrogen and oxygen gases. Third, electroplating: depositing a thin layer of one metal onto another using electric current, commonly seen in chromium plating on taps or gold plating on jewellery. Understanding these concepts helps explain everyday phenomena like the working of LED testers, battery chemistry, and corrosion prevention. The chapter uses simple experiments — testing liquids with a bulb circuit, observing gas bubbles during electrolysis, and demonstrating copper plating on metal keys — to build intuition. Mastery of this chapter requires memorising which liquids conduct electricity, knowing the conditions for electrolysis, and being able to describe the electroplating setup with anode, cathode, and electrolyte clearly.
  • Conductors vs insulators: saltwater, lemon juice, and vinegar conduct; distilled water, sugar solution, and alcohol do not
  • Electrolysis splits water into hydrogen (at cathode) and oxygen (at anode) in a 2:1 volume ratio
  • Electroplating uses a conducting solution (electrolyte), the object to be plated (cathode), and a plate of the coating metal (anode)
  • LED bulbs or magnetic compass can detect weak currents that tungsten bulbs cannot show

Worksheet Instructions and Format

This worksheet is designed for a 60-minute sitting and covers all question formats prescribed by CBSE for Class 8 Science. Difficulty level is Moderate, suitable for students who have completed the NCERT chapter at least once. Section A contains six multiple-choice questions (1 mark each), Section B has five fill-in-the-blank statements, Section C offers true/false statements, Section D presents five short-answer questions (2-3 marks each), Section E includes three long-answer and higher-order thinking (HOTS) questions (5 marks each), and finally one case-study question with sub-parts. Students should attempt all questions in one go to simulate exam conditions, then check the answer key provided at the end. Parents can use this worksheet for weekly practice or before unit tests. Print it double-sided to save paper, and encourage your child to write answers in full sentences for descriptive questions to build clarity and speed. This structured approach mirrors the actual board exam pattern and builds confidence in handling Chemical Effects of Electric Current topics.
  • Total marks: approximately 50 if marking scheme is applied (MCQ 1 mark, short 2-3 marks, long 5 marks)
  • No negative marking; attempt every question to maximise learning
  • Use a pencil for diagrams (anode-cathode setups, circuit diagrams) to ensure neatness
  • Refer to NCERT Class 8 Science textbook Chapter 11 if you get stuck, then re-attempt

Section A: Multiple Choice Questions (1 mark each)

Choose the correct option for each question. Each MCQ tests a single concept from conductivity, electrolysis, or electroplating. Read the question stem carefully, eliminate obviously wrong options, and select the best answer. Write only the letter (A/B/C/D) in your answer sheet. These questions often appear in the objective section of CBSE Class 8 Science term exams and are a quick way to score full marks if concepts are clear. Pay attention to keywords like 'best conductor', 'does not conduct', 'anode', 'cathode', and 'electrolyte' to avoid careless mistakes under time pressure.
  • Q1. Which of the following liquids is the best conductor of electricity? (A) Distilled water (B) Tap water (C) Saltwater solution (D) Sugar solution
  • Q2. During electrolysis of water, the gas collected at the cathode is: (A) Oxygen (B) Hydrogen (C) Nitrogen (D) Carbon dioxide
  • Q3. In electroplating, the object to be plated is made the: (A) Anode (B) Cathode (C) Electrolyte (D) Insulator
  • Q4. An LED glows even when a weak electric current flows through it. This property is useful to test: (A) Presence of magnetic field (B) Conductivity of liquids (C) Heat production (D) Light intensity
  • Q5. Which substance should be added to distilled water to make it a good conductor? (A) Sugar (B) Salt (C) Alcohol (D) Honey
  • Q6. The process of depositing a layer of zinc on iron to prevent rusting is called: (A) Electroplating (B) Electrorefining (C) Anodising (D) Galvanising

Section B: Fill in the Blanks (1 mark each)

Complete each statement with the correct technical term from the NCERT Class 8 Science Chapter 11 text. Write your answer in the space provided. These blanks test your recall of key definitions and processes. Read each sentence in full before filling in the word, because sometimes the grammar or context clues will guide you to the exact term needed. Common terms include 'electrolyte', 'anode', 'cathode', 'electroplating', 'electrolysis', 'conductor', 'insulator', and specific examples like 'copper sulphate' or 'dilute sulphuric acid'. Avoid spelling mistakes, as CBSE marking may deduct for incorrect spelling of scientific terms in descriptive papers.
  • Q7. The passage of electric current through a conducting solution causes __________ effects.
  • Q8. The positive terminal in an electrolytic cell is called the __________.
  • Q9. __________ is the process of coating one metal with another using electric current.
  • Q10. Pure or distilled water is a __________ conductor of electricity.
  • Q11. When electric current is passed through acidified water, __________ gas is liberated at the anode.

Section C: True or False (1 mark each)

Read each statement carefully and write True or False in your answer sheet. If the statement is false, you may be asked to correct it in the answer key for deeper understanding. These questions check common misconceptions — for example, many students think all liquids conduct electricity, or that hydrogen is produced at the anode during electrolysis. Cross-check your answers with the chapter summary in your NCERT Class 8 Science textbook to reinforce the correct facts. This section often appears in CBSE unit tests and helps build a strong factual foundation for application-based questions later in the worksheet.
  • Q12. Lemon juice is a good conductor of electricity.
  • Q13. In electroplating, the anode is made of the metal to be deposited.
  • Q14. Distilled water conducts electricity better than tap water.
  • Q15. An LED can detect very small electric currents.
  • Q16. During electrolysis of water, oxygen and hydrogen are produced in equal volumes.

Section D: Short Answer Questions (2-3 marks each)

Answer each question in two to four sentences. Use scientific terminology from the chapter and give reasoning or examples where asked. These questions typically carry 2 or 3 marks in CBSE Class 8 Science exams, so clarity and completeness matter. Start each answer with a direct statement, then explain or illustrate. For instance, if asked why distilled water does not conduct electricity, begin with 'Distilled water does not conduct electricity because it lacks free ions,' then elaborate on how dissolved salts provide ions that carry charge. Diagrams are not mandatory here but can earn you an extra mark if they clarify your explanation — for example, a simple circuit showing bulb, battery, and electrodes dipped in liquid. Practice writing these answers within three minutes each to match exam time constraints, and always end with a conclusion sentence if the question asks for reasoning or significance.
  • Q17. Why does an LED glow when connected to a cell and dipped in saltwater, but not when dipped in distilled water?
  • Q18. Explain the process of electrolysis of water with the help of the gases liberated at the two electrodes.
  • Q19. What is electroplating? Give one practical application of electroplating in daily life.
  • Q20. Distinguish between a good conductor and a poor conductor of electricity with two examples each.
  • Q21. Why is it advised not to touch electrical appliances with wet hands? Answer in terms of conductivity of water.

Section E: Long Answer and HOTS Questions (5 marks each)

These questions demand detailed explanations, diagrams, or multi-step reasoning. Allocate about eight to ten minutes per question. Structure your answer in clear paragraphs or numbered points: define the concept, describe the process or setup, explain the underlying chemistry or physics, and conclude with applications or significance. For example, when describing the electroplating process, first define it, then draw and label the setup (electrolyte, anode, cathode, battery), explain ion movement and metal deposition, and finally mention one real-world use like chromium plating on bike parts. HOTS (Higher Order Thinking Skills) questions test application and analysis — you might be asked to predict what happens if the electrolyte is changed, or to design an experiment to compare conductivity of different liquids. Use data, observations, and logical reasoning. These questions mirror the five-mark descriptive questions in CBSE board exams and are where clear, organized writing earns maximum credit. Reference NCERT Class 8 Science diagrams and experiment descriptions to ensure your answers align with board expectations.
  • Q22. Describe the process of electroplating with a neat labelled diagram. Explain why electroplating is important in industry.
  • Q23. Design an experiment to test whether a given liquid is a good conductor of electricity. List the materials required, procedure, observations, and conclusion.
  • Q24. A student connects an LED, a battery, and two electrodes dipped in three different liquids: tap water, saltwater, and sugar solution. Predict and explain in which cases the LED will glow brightly, dimly, or not at all. Justify your answer using the concept of ions.

Case-Study Question

Read the passage below carefully and answer the sub-questions that follow. Case studies test your ability to apply Chapter 11 concepts to real-world scenarios. Pay attention to details in the passage — quantities, observations, and conditions — because sub-questions often ask you to analyse or predict based on that context. This format has become common in recent CBSE papers and typically carries four to five marks in total. Write concise, direct answers referencing the passage where needed. Underline or highlight keywords in the passage before attempting the questions to save time and avoid missing critical information.

Complete Answer Key with Explanations

Below are the correct answers for all sections. Each answer includes a brief explanation or reasoning to help you understand why it is correct. Use this key only after attempting the worksheet yourself; self-checking builds exam confidence and helps identify weak areas. If you scored below seventy percent, revise the relevant NCERT Class 8 Science Chapter 11 sections and re-attempt the questions you got wrong. For MCQs, explanations clarify why distractors are incorrect. For descriptive answers, compare your phrasing with the model answer to improve clarity and completeness. Regular practice with such worksheets, combined with doubt-solving support, ensures strong performance in school exams. Platforms like CBSETUTOR.ai offer 24×7 AI-powered tutoring where students can upload this worksheet, get instant feedback, and clarify doubts via photo upload — all at a flat ₹999/month for any class from six to twelve, with a three-day free trial to try it risk-free.
  • Section A Answers: 1–C (Saltwater has maximum ions, conducts best), 2–B (Hydrogen is lighter, collects at cathode), 3–B (Object to be plated is cathode), 4–B (LED detects weak current to test conductivity), 5–B (Salt dissolves into ions), 6–D (Galvanising specifically refers to zinc coating for rust prevention)
  • Section B Answers: 7–chemical, 8–anode, 9–Electroplating, 10–poor, 11–oxygen
  • Section C Answers: 12–True, 13–True, 14–False (distilled water is a poor conductor), 15–True, 16–False (hydrogen and oxygen are produced in 2:1 volume ratio)
  • Section D Sample Answers: 17–Saltwater contains dissolved ions that carry electric charge, allowing current to flow and LED to glow; distilled water has no ions, so no current flows. 18–See worked example above. 19–Electroplating is depositing a metal layer on another object using current; e.g. chromium plating on taps for shine and rust resistance. 20–Good conductors (metals like copper, aluminium) allow current easily; poor conductors (rubber, wood) do not. 21–Wet hands have dissolved salts, making skin a better conductor and increasing shock risk.
  • Section E Sample Points: 22–See worked example above. 23–Materials: battery, LED, two electrodes, test liquid, beaker. Procedure: connect circuit, dip electrodes, observe LED. If it glows, liquid is a conductor. 24–LED glows brightly in saltwater (many ions), dimly in tap water (few ions), not at all in sugar solution (no ions).
  • Case Study Answers: (a) Both are poor conductors as they lack free ions. (b) Lemon juice and saltwater contain acids/salts that dissociate into ions, allowing current flow. (c) Bubbles indicate gas formation due to chemical decomposition (electrolysis).

Tips for Scoring Full Marks in Chapter 11

Chemical Effects of Electric Current is a high-scoring chapter if you focus on clarity and terminology. First, memorise the list of conductors and insulators from NCERT experiments — this alone secures marks in MCQs and fill-in-the-blanks. Second, practice drawing and labelling the electroplating setup at least five times so you can reproduce it neatly under exam pressure; labels must include 'anode', 'cathode', 'electrolyte', and 'battery'. Third, understand the difference between electrolysis (decomposition) and electroplating (deposition) conceptually, not just by rote. Fourth, use the term 'ions' correctly when explaining conductivity — saying 'dissolved particles' is vague and may cost you a mark. Fifth, for numerical or observation-based questions, always write the ratio 2:1 for hydrogen to oxygen in electrolysis of water; examiners check this specific detail. Sixth, in HOTS questions, apply the 'predict-explain-conclude' structure: predict the outcome, explain using chapter concepts, and conclude with a general principle. Finally, revise Activity 11.1 through 11.4 from the NCERT Class 8 Science textbook because board exams often frame questions around these exact experiments. Consistent worksheet practice and timely doubt resolution — available round the clock on CBSETUTOR.ai — will push your score above ninety percent in this chapter.
  • Always write chemical symbols correctly: H₂ for hydrogen, O₂ for oxygen, Cu for copper, Zn for zinc
  • Draw diagrams in pencil with a ruler; label neatly and use arrows to show current flow direction
  • For true/false, if asked to correct a false statement, rewrite the entire sentence with the correction underlined
  • In short answers, aim for three key points: definition, explanation, example or application

How CBSETUTOR.ai Supports Chapter 11 Mastery

After completing this worksheet, students often have lingering doubts about why certain liquids conduct or how to remember anode versus cathode. CBSETUTOR.ai provides a 24×7 AI tutor that answers such questions instantly. Simply snap a photo of any question from this worksheet or your NCERT Class 8 Science textbook, upload it, and receive a step-by-step explanation tailored to CBSE marking schemes. The platform covers every chapter and every class from six to twelve at a single flat fee of ₹999 per month — no hidden charges, no per-subject billing. Parents appreciate the transparency and the fact that their child can clarify doubts at midnight before an exam without waiting for tuition class. The AI tutor also generates additional practice questions similar to this worksheet, tracks progress over time, and highlights weak topics for focused revision. A three-day free trial lets families experience the benefit risk-free. For a chapter like Chemical Effects of Electric Current, where small conceptual gaps can cause mark loss, on-demand support makes the difference between good and excellent scores.
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Frequently asked questions

What is the difficulty level and suggested time for this Chemical Effects of Electric Current worksheet?+
This worksheet is of Moderate difficulty and is designed to be completed in 60 minutes. It suits students who have read the NCERT chapter at least once and are ready for structured practice before school unit tests or term exams.
How many marks is this Class 8 Science Chapter 11 worksheet worth if I follow the CBSE marking scheme?+
If you assign one mark per MCQ and fill-in-the-blank, two to three marks per short answer, and five marks per long answer and case-study sub-part, this worksheet totals approximately fifty marks. It mirrors the weightage and variety seen in actual board papers.
Can I use this worksheet for quick revision the night before my exam?+
Yes. Attempting all sections in one sitting and then reviewing the answer key will reinforce key definitions, processes, and applications. Focus especially on Section A and B for quick recall, and skim the long-answer model answers to recall structure and terminology.
Which topics from Chapter 11 are most frequently asked in CBSE Class 8 Science exams?+
Conductivity of liquids (which liquids conduct and why), the electrolysis of water (gases produced and their ratio), and electroplating (labelled diagram and applications) appear in almost every board and school exam. Ensure you can draw the electroplating setup and explain ion movement clearly.
Do I need to draw diagrams for the short-answer questions in Section D?+
Diagrams are not mandatory for short answers but can earn you an additional mark if they clarify your explanation. For example, a simple circuit diagram showing electrodes in liquid helps illustrate conductivity testing. Always label parts if you do draw.
What should I do if I score less than seventy percent on this worksheet?+
First, identify which sections you struggled with — MCQs suggest concept gaps, while poor performance in long answers indicates difficulty in structuring explanations. Reread the relevant NCERT Class 8 Science Chapter 11 sections, watch the experiments again, and re-attempt those questions after two days. Consider using CBSETUTOR.ai for instant doubt-solving and additional practice sets.
Are the terms 'anode' and 'cathode' interchangeable?+
No. The anode is always the positive electrode where oxidation (loss of electrons) occurs, and the cathode is the negative electrode where reduction (gain of electrons) happens. In electroplating, the object to be coated is the cathode. Mixing these terms will lose you marks in CBSE exams.
Why is distilled water a poor conductor even though tap water conducts electricity?+
Distilled water lacks dissolved salts and minerals, so it has very few free ions to carry electric charge. Tap water contains dissolved impurities that dissociate into ions, enabling current flow. This distinction is a favourite board-exam question.
How can I remember which gas is produced at which electrode during electrolysis of water?+
Use the mnemonic 'HOPE': Hydrogen at the neOative electrode (cathode), Oxygen at the Positive Electrode (anode). Also recall that hydrogen's volume is double that of oxygen, matching the H₂O formula.
Is galvanising the same as electroplating?+
Galvanising is a specific type of coating process where zinc is deposited on iron or steel to prevent rusting, usually done by dipping in molten zinc. Electroplating is the broader technique using electric current to deposit any metal onto another. The terms overlap but are not identical.
Can I practice more questions like this worksheet online for free?+
NCERT and CBSE websites provide sample papers, but for unlimited, chapter-specific practice with instant feedback, CBSETUTOR.ai offers a three-day free trial. You can upload any question, get step-by-step solutions, and generate similar questions for extra practice at ₹999/month for all subjects and classes.
What is the best way to prepare answers for the case-study question?+
Read the passage twice, underline key observations and data, then tackle each sub-question one by one. Refer back to the passage for specific details. Practice at least three to four case studies from past papers or guidebooks to get comfortable with this format, which is now standard in CBSE exams.

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