CBSE Class 12 Chemistry Exam 2025 is on February 27. It is important to score high marks through focused revision. For this purpose, subject experts have come up with a list of sure-shot questions in accordance with the new CBSE syllabus and exam pattern. These selected questions are high-weightage chapters and most frequently asked problems to facilitate strategic and efficient revision.
Also check: CBSE Class 12th Chemistry - Exam Pattern, Marking Scheme, and Weightage
Important Characteristics of Class 12 Chemistry Sure-Shot Questions
- Expert-Curated Questions – Based on trends and analysis of the previous years' exams.
- Covers High-Weightage Topics – Emphasizes key concepts most likely to be included in the exam.
- According to Latest CBSE Exam Pattern – Guarantees to be in sync with the CBSE Class 12 Chemistry 2025 syllabus.
- Includes Tricky & Application-Based Questions – Helps in improving problem-solving skills.
- Boosts Confidence & Time Management – Suitable for last-minute revision prior to the board exam.
Also check: CBSE Class 12 Chemistry Exam 2025: Top 50 MCQs with Answers
CBSE Class 12 Chemistry Board Exam Sure Shot Questions
1. Define the following terms:
(a) Molecularity of reaction
(b) Complex reaction
2. Calculate the molar mass of a compound when 6.3 g of it is dissolved in 27 g of chloroform to form a solution that has a boiling point of 68.04 °C. The boiling point of pure chloroform is 61.04 °C and K_b for chloroform is 3.63 °C kg mol⁻¹.
3. Write the stepwise mechanism of nucleophilic addition reactions in the carbonyl compounds.
OR
(b) How will you convert the following:
(i) Toluene to benzoic acid.
(ii) Ethanol to 3-Hydroxybutanal.
4. (a) What happens when Glucose reacts with HI? Write chemical equation.
(b) Which type of bond holds a DNA double helix together?
5.
(a) Which of the following compounds will react more rapidly by S_N2 reaction & why?
![Chemical structures in the image]
(b) Arrange the following compounds in the increasing order of their boiling points:
![Chemical structures in the image]
6. (a) Give chemical tests to distinguish between the following pairs of compounds:
(i) Phenol and Benzoic acid
(ii) Propanal and Propanone
(b) Which one of the given compounds is a stronger acid and why?
CH₂FCH₂CH₂COOH or CH₃CHFCH₂COOH
7. 24. Show that the time required for 99.9% completion in a first order reaction is 10 times of half-life (t₁/₂) of the reaction [log 2 = 0.3010, log 10 = 1].
8. Give reasons for the following:
(1) Methyl amine is more basic than aniline.
(2) Aniline readily reacts with bromine water to give 2, 4, 6-tribromoaniline.
(3) Primary amines have higher boiling points than tertiary amines.
9. 33. Attempt any five of the following:
(a) Why Zinc is not regarded as a transition element?
(b) What is Lanthanoid contraction?
(c) Why is first ionization enthalpy of chromium lower than that of Zn?
(d) Why are transition elements good catalysts?
(e) Compounds of transition metals are generally coloured. Give reason.
(f) Out of KMnO₄ and K₂MnO₄, which one is paramagnetic and why?
(g) Complete the following ionic equation:
Cr₂O₇²⁻ + 14 H⁺ + 6e⁻ →
10. An amide 'A' with molecular formula C-H₇ON undergoes Hoffmann Bromamide degradation reaction to give amine 'B'. 'B' on treatment with nitrous acid at 273-278 K form 'C' and on treatment with chloroform and ethanolic potassium hydroxide forms 'D'. 'C' on treatment with ethanol gives 'E'. Identify 'A', 'B', 'C', 'D' and 'E' and write the sequence of chemical equations.
11. Write the structures of A, B and C in the following reactions:
(a) CH₃ - CH₂ - Br → (KCN) → A → (OH⁻, Partial hydrolysis) → B → (NaOH + Br₂) → C
(b) NO₂-Benzene → (Fe + HCl) → A → (NaNO₂ + HCl, 273-278 K) → B → (C₂H₅OH) → C
12. The vapour pressure of a solvent at 283 K is 100 mm Hg. Calculate the vapour pressure of a dilute solution containing 1 mole of a strong electrolyte AB in 50 moles of the solvent at 283 K (assuming complete dissociation of solute AB).
13. Give the equations of reactions for the preparation of: (any three)
(a) Phenol from chlorobenzene
(b) Salicylaldehyde from phenol
(c) 2-Methoxyacetophenone from anisole
(d) Picric acid from phenol
14. Write the reaction involved in the following:
(a) Wolff-Kishner reduction
(b) Decarboxylation reaction
(c) Cannizzaro reaction
15.
(i) The resistance of 0.05 M CH₃COOH solution is found to be 100 ohm. If the cell constant is 0.0354 cm⁻¹, calculate the molar conductivity of the acetic acid solution.
(ii) State Faraday’s first law of electrolysis. How much charge in Faraday is required for the reduction of 1 mol of MnO₄ to Mn²⁺?
Also check: CBSE Class 12th Chemistry Board Exam 2025: Last-Minute Answer Writing Tips
