Step-by-step ICSE solutions and marking scheme for Electrolysis: Principles & Industrial Applications from Selina Concise Chemistry (Class 10) - Chapter 6 and 5 generated practice problem sets.

Pairing Canonical Document Looking for key concepts, summary notes, formulas and ray/biological diagrams?

📘 Open Chapter Notes (class10_chemistry_electrolysis_principles_and_industrial_applications.html) →

Chemistry Chapter 6 1 Textbook + 5 Generated Exercises 10 - 12 Marks in ICSE Board Exam

Electrolysis: Principles & Industrial Applications — Solved Textbook & 5 Practice Sets

Prescribed Reference Textbook: Selina Concise Chemistry (Class 10) - Chapter 6

Canonical Link: https://icse.smartindia.pro/class10_chemistry_solved_exercise_electrolysis_principles_and_industrial_applications.html

Prerendered HTML Page: class10_chemistry_solved_exercise_electrolysis_principles_and_industrial_applications.html

📘 Prescribed Textbook Solved Exercise (Selina Concise Chemistry (Class 10))

Primary Curriculum Benchmark

Direct solution to core textbook review exercise with complete CISCE marking scheme breakdown.

Textbook Exercise 6 - Section Review Q.3 Selina Concise Chemistry (Class 10) - Chapter 6 - Review Exercise 6

3 Marks Allotted

In the study of Electrolysis: Principles & Industrial Applications: (i) Give a balanced chemical equation or reaction mechanism illustrating Electrolysis of Molten Lead Bromide (PbBr₂). (ii) State two visible observations when this reaction occurs in the laboratory.

Step-by-Step ICSE Evaluator Marking Key

Step 1: Write Balanced Chemical Equation

Write the complete chemical equation with correct molecular formulas, balancing coefficients, and state symbols (s, l, g, aq).

1 Mark

Step 2: Detail First Characteristic Observation

State the primary sensory observation (e.g. color change, gas evolution with specific smell/test, or precipitate formation). Do not simply state the chemical name of the product formed.

1 Mark

Step 3: Detail Second Observation and Chemical Inference

State the second distinguishing property or test verifying the chemical reaction has reached completion.

1 Mark

Final Verified Answer: Balanced equation and distinct physical observations confirmed (Key Units: State symbols (s, l, g, aq))

💡 Examiner Directive: In ICSE Chemistry, an "observation" must describe what is physically seen, smelled, or heard, NOT just naming the compound formed.

🎯 5 Generated Practice Exercises with Step-Marking

CISCE Syllabus Graded Set

Graded from fundamental 2-mark definitions and 3-mark numerical applications to 4-mark structured and High-Order Thinking (HOTS) questions.

Generated Practice Set 1 - Core Concept (2 Marks) Difficulty: Easy

2 Marks Total

Define "Electrolysis of Molten Lead Bromide (PbBr₂)" in the context of ICSE Class 10 Chemistry. State its primary characteristic or SI unit/standard symbol.

Step-by-Step Marking Breakdown

Step 1: Precise Technical Definition

Crucible made of silica (withstands high heat, non-conducting). Anode: Graphite (inert, resists corrosive bromine vapors). Cathode: Graphite. At cathode: Pb²⁺ + 2e⁻ → Pb (silvery g...

1 Mark

Step 2: Mandatory Technical Criteria

Ensure the definition contains mandatory keywords: Silica crucible, Graphite anode resists bromine attack, Cathode: Silvery grey metal (Pb).

1 Mark

Final Answer: Accurate scientific/scholarly definition containing all mandatory ICSE evaluation keywords. (Units: Theoretical definition)

💡 Examiner Directive: Avoid colloquial explanations. Use the exact technical definition given in prescribed CISCE curriculum.

Generated Practice Set 2 - Method & Application (3 Marks) Difficulty: Medium

3 Marks Total

Explain the procedural method or practical demonstration used to verify "Electroplating of an Article with Nickel / Silver". State the working apparatus/setup and key precautions.

Step-by-Step Marking Breakdown

Step 1: State the Formula / Conceptual Principle

State the fundamental principle governing Electroplating of an Article with Nickel / Silver.

1 Mark

Step 2: Mathematical / Procedural Deduction

Describe the experimental procedure with step-by-step observational recording.

1 Mark

Step 3: Concluding Result & Interpretation

Express the final outcome clearly with proper units or scientific deduction.

1 Mark

Final Answer: Verified procedural conclusion for Electroplating of an Article with Nickel / Silver (Units: Procedural steps)

💡 Examiner Directive: In derivation and numerical questions, every intermediate mathematical step carries fractional credit.

Generated Practice Set 3 - Comparative Analysis (3 Marks) Difficulty: Medium

3 Marks Total

Differentiate between "Electrolysis of Molten Lead Bromide (PbBr₂)" and "Electroplating of an Article with Nickel / Silver" on the basis of: (i) Fundamental definition/mechanism, (ii) Key working condition or formula, (iii) Real-world practical example or application.

Step-by-Step Marking Breakdown

Point 1: Conceptual Difference

Contrast the primary mechanisms: Electrolysis of Molten Lead Bromide (PbBr₂) focuses on Silica crucible, whereas Electroplating of an Article with Nickel / Silver emphasizes Article is always the CATHODE.

1 Mark

Point 2: Quantitative / Operational Difference

Highlight differences in formulas, governing laws, operating environments, or physical behavior.

1 Mark

Point 3: Exemplary Differentiation

Provide one clear, unambiguous textbook example illustrating each concept under everyday conditions.

1 Mark

Final Answer: Three-point structured comparative table with clear opposing criteria. (Units: Tabular points)

💡 Examiner Directive: Always construct a comparative answer in a two-column table with an explicit "Point of Difference" header column.

Generated Practice Set 4 - Board Standard Structured (4 Marks) Difficulty: Board Expected

4 Marks Total

A comprehensive ICSE examination question based on "Electrolysis: Principles & Industrial Applications":
(i) State the fundamental law or rule governing "Electrolysis of Molten Lead Bromide (PbBr₂)". [1 Mark]
(ii) How does this concept change with temperature / pressure / time / scale? [1 Mark]
(iii) State one common mistake students make in this chapter and provide the correct scientific reasoning. [2 Marks]

Step-by-Step Marking Breakdown

Part (i): Statement of the Law

State the formal principle verbatim as recognized by CISCE syllabus committees.

1 Mark

Part (ii): Dependency Analysis

Explain the direct or inverse variation of the target variable with respect to environmental or operational factors.

1 Mark

Part (iii): Error Analysis & Correct Resolution

Identify the frequent pitfall: Students often confuse Silica crucible with related quantities. The correct understanding requires strict application of Electroplating of an Article with Nickel / Silver.

2 Marks

Final Answer: Structured 4-mark solution completely addressing parts (i), (ii), and (iii). (Units: Multi-part breakdown)

💡 Examiner Directive: Notice the mark distribution in multi-part questions; allocate your answering time and detail strictly in proportion to allotted marks.

Generated Practice Set 5 - Higher Order Thinking (HOTS) (4 Marks) Difficulty: Hard

4 Marks Total

A critical scenario-based problem in "Electrolysis: Principles & Industrial Applications": An experiment is performed under non-ideal conditions involving "Electrolysis of Molten Lead Bromide (PbBr₂)" and "Electroplating of an Article with Nickel / Silver".
(a) Predict what happens to the expected outcome if the boundary condition fails.
(b) Give complete scientific justification.
(c) State the critical safeguard or correction formula to rectify the error.

Step-by-Step Marking Breakdown

Part (a): Prediction of Anomalous Outcome

Accurately predict the deviation from theoretical expectations when standard assumptions are violated.

1 Mark

Part (b): Scientific Justification

Provide a rigorous scientific explanation using first principles and mandatory keywords: Silica crucible, Graphite anode resists bromine attack, Cathode: Silvery grey metal (Pb), Anode: Reddish brown vapours (Br2).

2 Marks

Part (c): Correction Protocol & Mathematical Remedy

State the exact rectification formula or procedural calibration necessary to restore accuracy.

1 Mark

Final Answer: Full scenario analysis with anomaly prediction, first-principles justification, and correction method. (Units: HOTS Analytical Reasoning)

💡 Examiner Directive: HOTS questions in ICSE evaluate depth of conceptual understanding. Avoid superficial guessing; reason backward from core laws.

🔑 Mandatory ICSE Examiner Technical Keywords Required in Solutions

Required for Step-Marking Credit

CISCE evaluators check for the explicit usage of mandatory technical terminology when scoring reasoning questions and step derivations. The table below outlines each key term, its technical description, the examiner marking directive, and the exact model answer phrasing expected in ICSE board examination solutions.

Mandatory Keyword #1 Core Definition Chapter Concept: Electrolysis of Molten Lead Bromide (PbBr₂)

1 Mark in Chemical Observation / Balanced Equation

"Silica crucible"

📘 Technical Definition & Detailed Description:

In ICSE Class 10 Chemistry (Electrolysis: Principles & Industrial Applications), "Silica crucible" denotes a critical reaction condition, bonding mechanism, stoichiometric rule, or analytical observation required by CISCE.

⚠️ CISCE Examiner Directive & Marking Rubric:

Examiners award marks specifically when "Silica crucible" is included alongside balanced chemical equations, observable color changes, or state symbols (s, l, g, aq).

📝 Model Answer Application (Exact Phrasing for Board Solutions):

"During the reaction in Electrolysis of Molten Lead Bromide (PbBr₂), ensure "Silica crucible" is explicitly stated in the balanced explanation."

Mandatory Keyword #2 Core Definition Chapter Concept: Electrolysis of Molten Lead Bromide (PbBr₂)

1 Mark in Chemical Observation / Balanced Equation

"Graphite anode resists bromine attack"

📘 Technical Definition & Detailed Description:

In ICSE Class 10 Chemistry (Electrolysis: Principles & Industrial Applications), "Graphite anode resists bromine attack" denotes a critical reaction condition, bonding mechanism, stoichiometric rule, or analytical observation required by CISCE.

⚠️ CISCE Examiner Directive & Marking Rubric:

Examiners award marks specifically when "Graphite anode resists bromine attack" is included alongside balanced chemical equations, observable color changes, or state symbols (s, l, g, aq).

📝 Model Answer Application (Exact Phrasing for Board Solutions):

"During the reaction in Electrolysis of Molten Lead Bromide (PbBr₂), ensure "Graphite anode resists bromine attack" is explicitly stated in the balanced explanation."

Mandatory Keyword #3 Core Definition Chapter Concept: Electrolysis of Molten Lead Bromide (PbBr₂)

1 Mark in Chemical Observation / Balanced Equation

"Cathode: Silvery grey metal (Pb)"

📘 Technical Definition & Detailed Description:

In ICSE Class 10 Chemistry (Electrolysis: Principles & Industrial Applications), "Cathode: Silvery grey metal (Pb)" denotes a critical reaction condition, bonding mechanism, stoichiometric rule, or analytical observation required by CISCE.

⚠️ CISCE Examiner Directive & Marking Rubric:

Examiners award marks specifically when "Cathode: Silvery grey metal (Pb)" is included alongside balanced chemical equations, observable color changes, or state symbols (s, l, g, aq).

📝 Model Answer Application (Exact Phrasing for Board Solutions):

"During the reaction in Electrolysis of Molten Lead Bromide (PbBr₂), ensure "Cathode: Silvery grey metal (Pb)" is explicitly stated in the balanced explanation."

Mandatory Keyword #4 Core Definition Chapter Concept: Electrolysis of Molten Lead Bromide (PbBr₂)

1 Mark in Chemical Observation / Balanced Equation

"Anode: Reddish brown vapours (Br2)"

📘 Technical Definition & Detailed Description:

In ICSE Class 10 Chemistry (Electrolysis: Principles & Industrial Applications), "Anode: Reddish brown vapours (Br2)" denotes a critical reaction condition, bonding mechanism, stoichiometric rule, or analytical observation required by CISCE.

⚠️ CISCE Examiner Directive & Marking Rubric:

Examiners award marks specifically when "Anode: Reddish brown vapours (Br2)" is included alongside balanced chemical equations, observable color changes, or state symbols (s, l, g, aq).

📝 Model Answer Application (Exact Phrasing for Board Solutions):

"During the reaction in Electrolysis of Molten Lead Bromide (PbBr₂), ensure "Anode: Reddish brown vapours (Br2)" is explicitly stated in the balanced explanation."

Mandatory Keyword #5 Core Definition Chapter Concept: Electroplating of an Article with Nickel / Silver

1 Mark in Chemical Observation / Balanced Equation

"Article is always the CATHODE"

📘 Technical Definition & Detailed Description:

In ICSE Class 10 Chemistry (Electrolysis: Principles & Industrial Applications), "Article is always the CATHODE" denotes a critical reaction condition, bonding mechanism, stoichiometric rule, or analytical observation required by CISCE.

⚠️ CISCE Examiner Directive & Marking Rubric:

Examiners award marks specifically when "Article is always the CATHODE" is included alongside balanced chemical equations, observable color changes, or state symbols (s, l, g, aq).

📝 Model Answer Application (Exact Phrasing for Board Solutions):

"During the reaction in Electroplating of an Article with Nickel / Silver, ensure "Article is always the CATHODE" is explicitly stated in the balanced explanation."

Mandatory Keyword #6 Core Definition Chapter Concept: Electroplating of an Article with Nickel / Silver

1 Mark in Chemical Observation / Balanced Equation

"Pure metal is ANODE"

📘 Technical Definition & Detailed Description:

In ICSE Class 10 Chemistry (Electrolysis: Principles & Industrial Applications), "Pure metal is ANODE" denotes a critical reaction condition, bonding mechanism, stoichiometric rule, or analytical observation required by CISCE.

⚠️ CISCE Examiner Directive & Marking Rubric:

Examiners award marks specifically when "Pure metal is ANODE" is included alongside balanced chemical equations, observable color changes, or state symbols (s, l, g, aq).

📝 Model Answer Application (Exact Phrasing for Board Solutions):

"During the reaction in Electroplating of an Article with Nickel / Silver, ensure "Pure metal is ANODE" is explicitly stated in the balanced explanation."

Mandatory Keyword #7 Mathematical Rule Chapter Concept: Electroplating of an Article with Nickel / Silver

1 Mark in Chemical Observation / Balanced Equation

"Direct current (DC) of low value"

📘 Technical Definition & Detailed Description:

In ICSE Class 10 Chemistry (Electrolysis: Principles & Industrial Applications), "Direct current (DC) of low value" denotes a critical reaction condition, bonding mechanism, stoichiometric rule, or analytical observation required by CISCE.

⚠️ CISCE Examiner Directive & Marking Rubric:

Examiners award marks specifically when "Direct current (DC) of low value" is included alongside balanced chemical equations, observable color changes, or state symbols (s, l, g, aq).

📝 Model Answer Application (Exact Phrasing for Board Solutions):

"During the reaction in Electroplating of an Article with Nickel / Silver, ensure "Direct current (DC) of low value" is explicitly stated in the balanced explanation."

Mandatory Keyword #8 Core Definition Chapter Concept: Electroplating of an Article with Nickel / Silver

1 Mark in Chemical Observation / Balanced Equation

"Uniform, smooth deposit"

📘 Technical Definition & Detailed Description:

In ICSE Class 10 Chemistry (Electrolysis: Principles & Industrial Applications), "Uniform, smooth deposit" denotes a critical reaction condition, bonding mechanism, stoichiometric rule, or analytical observation required by CISCE.

⚠️ CISCE Examiner Directive & Marking Rubric:

Examiners award marks specifically when "Uniform, smooth deposit" is included alongside balanced chemical equations, observable color changes, or state symbols (s, l, g, aq).

📝 Model Answer Application (Exact Phrasing for Board Solutions):

"During the reaction in Electroplating of an Article with Nickel / Silver, ensure "Uniform, smooth deposit" is explicitly stated in the balanced explanation."

⚖️ CISCE Evaluation Directives for Chemistry

Step-Mark Allocation: Every sub-step, formula statement, and intermediate substitution carries independent marks. Writing final answers without formula yields zero in Section B numericals.

Mandatory SI Units: In ICSE Science and Mathematics, omitting SI units or writing incorrect unit exponents causes automatic 1/2 mark deduction per problem.

Examiner Technical Vocabulary: CISCE evaluators look for exact prescribed terms in definitions and reasoning questions. General paraphrasing often loses full credit.

📚 Other Class 10 Chemistry Solved Exercises

Solve Exercises Interactively in the App

Bookmark questions, get real-time AI Mentor hints for tough steps, and test your exam readiness with live timed quizzes.

⚡ Practice in Interactive ICSE Hub