Welcome to the complete, 100% textbook-grounded CG Board Class 8 Science Chapter 11 Solutions: Chemical Effects of Electric Current (विद्युत धारा के रासायनिक प्रभाव) in Bilingual Format (English Medium + हिंदी माध्यम). Every in-text question (Answer these / इनके उत्तर दीजिए) and end-of-chapter exercise (Exercises / अभ्यास के प्रश्न) has been solved strictly from the official 2026-27 SCERT Chhattisgarh Raipur textbook.
Options: (a) Electric cell (b) Voltameter (c) Ammeter (d) Magnetic needle
(b) Voltameter
Answer:Dilute sulphuric acid
(ii) On passing current through any solution, produces ……………………. effect.
Answer:chemical
(iii) In solar cell …………… energy is converted into …………………………… energy.
Answer:solar (or light), electrical
(iv) Process of coating of expensive metals over cheap metals by voltaic cell is called …………..
Answer:electroplating
(v) …………… cells are used in watches, calculator, transistors and artificial satellites.
Answer:Solar (and Button)
Question 2
Answer the following questions
क्या आसुत जल विद्युत का चालन करता है…
📝 Question:
Answer the following questions:**
English: In case of fire, before the fireman uses the water hose they shut off the main electrical supply for the area. Explain why they do this?
English: Why is iron coated with zinc?
English: Explain the process of electrolysis?
💡 Solution:
Does distilled water conduct electricity? If not what can we do to make it a conductor?
No, distilled water does not conduct electricity because it is completely free of dissolved salts and ions. To convert it into a conductor, we can add and dissolve a few drops of an acid (such as dilute hydrochloric acid or sulphuric acid), a base (such as caustic soda / sodium hydroxide), or a pinch of common salt (sodium chloride). Dissolving these substances introduces free positive and negative ions that carry electric current through the water.
Answer:
English: The tap water or ground water used by firemen contains naturally dissolved mineral salts, making it a good conductor of electricity. If the main electrical supply is not turned off, high voltage electric current can travel back through the continuous stream of water to the firemen, resulting in severe or fatal electric shocks. Therefore, shutting off the main electrical supply is an essential safety precaution.
Answer:
English: Iron is a highly reactive structural metal that undergoes rusting and corrosion when exposed to atmospheric moisture and oxygen. Rusting weakens iron structures like bridges, automobiles, and roof sheets. Zinc is resistant to atmospheric corrosion. Depositing a protective layer of zinc over iron (a process known as galvanization) prevents iron from coming into direct contact with air and moisture, thereby halting rust formation.
Answer:
English:
📝 प्रश्न:
Answer the following questions:**
English: In case of fire, before the fireman uses the water hose they shut off the main electrical supply for the area. Explain why they do this?
English: Why is iron coated with zinc?
English: Explain the process of electrolysis?
💡 उत्तर / हल:
Does distilled water conduct electricity? If not what can we do to make it a conductor?
No, distilled water does not conduct electricity because it is completely free of dissolved salts and ions. To convert it into a conductor, we can add and dissolve a few drops of an acid (such as dilute hydrochloric acid or sulphuric acid), a base (such as caustic soda / sodium hydroxide), or a pinch of common salt (sodium chloride). Dissolving these substances introduces free positive and negative ions that carry electric current through the water.
Answer:
English: The tap water or ground water used by firemen contains naturally dissolved mineral salts, making it a good conductor of electricity. If the main electrical supply is not turned off, high voltage electric current can travel back through the continuous stream of water to the firemen, resulting in severe or fatal electric shocks. Therefore, shutting off the main electrical supply is an essential safety precaution.
Answer:
English: Iron is a highly reactive structural metal that undergoes rusting and corrosion when exposed to atmospheric moisture and oxygen. Rusting weakens iron structures like bridges, automobiles, and roof sheets. Zinc is resistant to atmospheric corrosion. Depositing a protective layer of zinc over iron (a process known as galvanization) prevents iron from coming into direct contact with air and moisture, thereby halting rust formation.
Answer:
English:
Question 3
Definition Electrolysis is the chemical process in which…
Definition Electrolysis is the chemical process in which…
📝 Question:
Definition:** Electrolysis is the chemical process in which a conducting solution (electrolyte) decomposes into its positive and negative ions due to the passage of an electric current.
English: Name the electrolyte, positive terminal and negative terminal of button cell.
English: Write 3 uses of electroplating.
💡 Solution:
2. Experimental Setup (Voltameter): The complete apparatus is called a voltameter. It consists of a glass container filled with an electrolyte and two metal rods or plates called electrodes dipped in it.
Anode: The electrode connected to the positive terminal of the battery.
Cathode: The electrode connected to the negative terminal of the battery.
3. Working Process: When the electric circuit is closed, current flows from anode to cathode in the external circuit, and inside the solution, current flows from cathode to anode. The electric current breaks down the electrolyte into cations (positive ions) and anions (negative ions). Cations move toward the cathode and gain electrons, while anions move toward the anode and lose electrons.
4. Balanced Chemical Reaction Example (Dissociation of Copper Sulphate Solution):
Copper Sulphate (CuSO4) → [Electric / Current] Copper Ion (Cu2+) + Sulphate Ion (SO42-)
At Cathode (Negative Electrode):
Cu2+ + 2e^- → Cu(s) (Copper metal deposits on cathode)
Positive Terminal (Anode): Zinc (Zn) or Aluminum (Al).
Negative Terminal (Cathode): Silver oxide (Ag_2O) or Mercury oxide (HgO).
Electrolyte: Paste of Sodium hydroxide (NaOH) or Potassium hydroxide (KOH) / Sodium or Potassium oxide.
Answer:
English: Three major uses of electroplating are:
Protection Against Corrosion and Rust: Iron parts of bridges, automobiles, and building materials are electroplated with zinc (galvanization) or chromium to protect them from rusting and atmospheric decay.
Decorative & Affordable Items: Base metals are electroplated with precious metals like gold or silver to make attractive, durable, and inexpensive artificial ornaments and utensils.
Protection of Stored Food: Iron cans used for storing food are electroplated with tin; because tin is less reactive than iron, it prevents food from spoiling due to direct contact with iron.
📝 प्रश्न:
Definition:** Electrolysis is the chemical process in which a conducting solution (electrolyte) decomposes into its positive and negative ions due to the passage of an electric current.
English: Name the electrolyte, positive terminal and negative terminal of button cell.
English: Write 3 uses of electroplating.
💡 उत्तर / हल:
2. Experimental Setup (Voltameter): The complete apparatus is called a voltameter. It consists of a glass container filled with an electrolyte and two metal rods or plates called electrodes dipped in it.
Anode: The electrode connected to the positive terminal of the battery.
Cathode: The electrode connected to the negative terminal of the battery.
3. Working Process: When the electric circuit is closed, current flows from anode to cathode in the external circuit, and inside the solution, current flows from cathode to anode. The electric current breaks down the electrolyte into cations (positive ions) and anions (negative ions). Cations move toward the cathode and gain electrons, while anions move toward the anode and lose electrons.
4. Balanced Chemical Reaction Example (Dissociation of Copper Sulphate Solution):
Copper Sulphate (CuSO4) → [Electric / Current] Copper Ion (Cu2+) + Sulphate Ion (SO42-)
At Cathode (Negative Electrode):
Cu2+ + 2e^- → Cu(s) (Copper metal deposits on cathode)
Positive Terminal (Anode): Zinc (Zn) or Aluminum (Al).
Negative Terminal (Cathode): Silver oxide (Ag_2O) or Mercury oxide (HgO).
Electrolyte: Paste of Sodium hydroxide (NaOH) or Potassium hydroxide (KOH) / Sodium or Potassium oxide.
Answer:
English: Three major uses of electroplating are:
Protection Against Corrosion and Rust: Iron parts of bridges, automobiles, and building materials are electroplated with zinc (galvanization) or chromium to protect them from rusting and atmospheric decay.
Decorative & Affordable Items: Base metals are electroplated with precious metals like gold or silver to make attractive, durable, and inexpensive artificial ornaments and utensils.
Protection of Stored Food: Iron cans used for storing food are electroplated with tin; because tin is less reactive than iron, it prevents food from spoiling due to direct contact with iron.