ISC Class 12 Chemistry Exam 2026 Repeated Questions are from the important concepts with maximum-weightage chapters, such as Solid States, Solutions, Electrochemistry, Chemical Kinetics in Physical Chemistry. From the Inorganic Chemistry, the important topics from which the questions could be repeated are p-, d-, and f-Block Elements, Coordination Compounds, General Principles and Metallurgy, and in Organic Chemistry, Haloalkanes and Haloarenes, Alcohols, Phenols, and Ethers, etc. Solving these topics will help you in your targeted preparation. You can also check the ISC Class 12 Chemistry Weightage 2026 here.

Knowing these questions will help you focus your efforts on the key topics and concepts that have a higher chance of coming up in the exam. This will also enhance your speed, accuracy, and time management. Moreover, solving these questions will make you confident in handling different types of questions within the given time. We have provided some of the repeated questions asked from the ISC Class 12 Chemistry previous year question papers. Continue reading the article to have an idea of the ISC Class 12 Chemistry Exam 2026 Repeated Questions.

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ISC Class 12 Chemistry Exam 2026 Repeated Questions

• The addition of a non-volatile solute to a pure solvent ________ its vapour pressure and ________ its boiling point.
• When the concentration of a reactant of a first-order reaction is doubled, the rate becomes ________ times but for ________ order reaction the rate remains the same.
• Phenol when treated with bromine water produces ________, which is an example of ________ substitution reaction. Methyl chloride on treatment with ________ gives methyl cyanide, whereas on treatment with ________, it gives methyl isocyanide.
• When Chlorobenzene is heated with aq. ammonia in the presence of Cu₂O at high pressure, it gives:
  • (a) aniline (b) phenyl isocyanide (c) diphenyl (d) diphenylamine
• Hydrolysis of sucrose is called (a) esterification (b) saponification (c) hydration, or (d) inversion
• Consider yourself a research scholar in the forensic science department studying the age of a dead biological sample. During one of the studies, you found that the sample decomposed by following first-order kinetics. If 50% of the sample is decomposed in 120 minutes, how long will it take for 90% of the sample to decompose?
• Using IUPAC nomenclature, write the formula for each of the following:
  • (i) hexaamminecobalt (III) sulphate (ii) tetraaquadichloridochromium (III) nitrate
  • (ii) Answer the following questions. (a) Specific conductance of a solution decreases upon dilution. Why? (b) The emf of a cell should be positive for a spontaneous reaction. Give a reason. (c) Name the type of cell in which the reaction occurs only in one direction and cannot be reversed by an external energy source. Write any one disadvantage of this type of cell.
• Write the chemical test to distinguish between each of the following pairs of compounds. (i) Ethanol and propan-1-al (ii) Phenol and benzoic acid.
• Write chemical equations to illustrate the following name reactions: (i) Finkelstein reaction (ii) Williamson’s synthesis (iii) Reimer–Tiemann reaction
• Phenol is an aromatic alcohol that is used to prepare many important compounds, such as picric acid. Phenol is widely used in household and industrial settings as a cleaner and disinfectant. It is also used as a primary chemical to make plastics. Phenol is less soluble in water as compared to aliphatic alcohol. Some aliphatic alcohols are toxic and can be addictive.
  • (i) How is the acid mentioned above prepared from phenol? Write the chemical reaction involved in this preparation.
  • (ii) ‘Phenol is less soluble in water as compared to aliphatic alcohol.’ Explain.
  • (iii) Write the chemical equation for the preparation of phenol from chlorobenzene.
  • (iv) An organic compound [A] having molecular formula C₄H₁₀O gives a positive Lucas test within five minutes at room temperature. Compound [A] upon oxidation with K₂Cr₂O₇/H₂SO₄ forms a compound [B] that does not respond to Tollen’s test. Identify compound [A].
  • (v) In the above reaction, compound [B] gets reduced with Zn/Hg and HCl and forms compound (C). Identify compound [C] and write the balanced reaction for the conversion of compound [B] to compound [C].
• Given below are two statements marked Assertion and Reason. Read the two statements carefully and select the correct option.
  • Assertion: The Zr–Hf pair of elements has the same value of atomic radii, though Zr and Hf are placed in different periods in the periodic table.
  • Reason: The lanthanoid contraction prevents the expected increase in atomic radii of Hf. (a) Both Assertion and Reason are true and Reason is the correct explanation for Assertion. (b) Both Assertion and Reason are true but Reason is not the correct explanation for Assertion. (c) Assertion is true and Reason is false. (d) Both Assertion and Reason are false.
• Calculate the number of coulombs required to electroplate 4.75 g of aluminium when electrode reaction is Al³⁺ + 3e⁻ → Al (Given: Atomic weight of Al = 27 g mol⁻¹, 1 Faraday = 96,500 coulombs)

The questions given above are analyzed based on ISC Class 12 Chemistry Previous Year Question Papers . You can focus on these and the questions similar to these. All these questions will carry maximum marks and have a high probability of reappearing in the upcoming exam. Hope that this will help you in your final preparation.