CBSE Class 12 Chemistry Pre-Board Sample Paper 2025 With Solutions, Download PDF
The CBSE Class 12 Chemistry Pre-Board Exam is an important academic journey. It helps you assess your preparation level and identify areas that require more attention. This sample paper is designed to provide you with a realistic exam experience and help you strategize your study plan.
CBSE Class 12 Chemistry Pre-Board Sample Paper: This sample paper is designed to provide you with a realistic exam experience and help you strategize your study plan. To achieve this, they conduct several pre-board exams that give the actual board exam environment. These pre-board exams help students get familiar with the exam format, boost their confidence, and motivate them to study effectively. The performance in the pre-board exams is often a good indicator of how well students will do in the final board exams. Here, the pre-board question paper for Class 12 Chemistry is provided, along with possible solutions for Section A. Students are encouraged to attempt the paper, check their answers, and discuss them with their teacher to ensure proper understanding and preparation.
CBSE Class 12 Chemistry Pre-Board Sample Paper
General Instructions:
Read the following instructions very carefully and follow them:
Read the following instructions carefully.
(a) There are 33 questions in this question paper with internal choice.
(b) SECTION A consists of 16 multiple -choice questions carrying 1 mark each.
(c) SECTION B consists of 5 short answer questions carrying 2 marks each.
(d) SECTION C consists of 7 short answer questions carrying 3 marks each.
(e) SECTION D consists of 2 case - based questions carrying 4 marks each
(f) SECTION E consists of 3 long answer questions carrying 5 marks each.
(g) All questions are compulsory.
(h) Use of log tables and calculators is not allowed.
Section - A
Multiple Choice Questions:
1. Number of Faradays (F) required to reduce 1 mole of MnO4– ion into Mn2+ are
(a) 7F (b) 2F (c) 1F (d) 5F
ans. (a) 7F
2. The half-life of a first order reaction is 69.35 s. The value of rate constant of the reaction is
(a) 1.0 s−1
(b) 0.1 s−1
(c) 0.01 s−1
(d) 0.001 s−1
ans. (a) 1.0 s−1
3. The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.
(a) 3d7 (b) 3d5 (c) 3d8 (d) 3d2
ans. (b) 3d5
4. A tertiary alcohol is obtained by the reaction of Grignard reagent with:
(a) Butanone (b) Propanone (c) Acetone (d) All of the above
ans. (c) Acetone
5. An organic compound X on treatment with pyridinium chlorochromate in dichloromethane gives compound Y. Compound Y reacts with I2 and alkali to form triiodo methane. The compound ‘X’ is:
(a)CH3CH2OH (b)CH3CHO (c)CH3COCH3 (d)CH3COOH
ans. CH3COCH3
6. Which of the following statements are not true about glucose?
(a) It is an aldohexose (b) On heating with HI, it forms n-hexane
(c) It is present in furanose form (d) It does not give 2,4-DNP test
ans. d) It does not give 2,4-DNP test
7. Lanthanoid contraction is due to
a) decrease of valence electrons
b) poor shielding effect of 4f
c) decrease of effective nuclear charge
d) increase of valence electrons
ans. (b) Poor shielding effect of 4f
8. For a reaction x + y → z, rate ∝ |X|. What is (i) molecularity and (ii) order ofreaction?
a) (i)2, (ii) 1
b) (i)2, (ii) 2
c) (i) 1, (ii) 1
d) (i) 1, (ii) 2
ans. (c) (i) 1, (ii) 1
9. It is called ether when the alkyl groups connected to either side of the oxygen atom in an ether are different.
a) mixed
b) symmetrical
c) simple
d) diethyl
ans. (a) Mixed
10. By reacting with which of the following, primary amines can be distinguished from secondary and tertiary amines?
a) Chloroform alone
b) Methyl iodide
c) Chloroform and alcoholic KOH
d) Zinc dust
ans. (c) Chloroform and alcoholic KOH
11. The charge required for the reduction of 1 mol of MnO4– to MnO2 is
(a) 1 F
(b) 3 F
(c) 5 F
(d) 6 F
ans. (b) 3 F
12. In which of the following reactions acetamide is converted to methanamine
a) Gabriel phthalimide synthesis
b) Carbylamine reaction
c) Stephen’s reaction
d) Hoffmann bromamide reaction
ans. (d) Hoffmann bromamide reaction
For Q No. 13 to 16, two statements are given-one labelled as Assertion(A) and the other labelled as Reason(R). Select the most appropriate answer from the options given below:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
13. Assertion(A): Rate constant of a zero-order reaction has the same unit as the rate of a reaction.
Reason(R): Rate constant of a zero-order reaction does not depend upon the concentration of the reactant.
ans. (a) Both A and R are true and R is the correct explanation of A
14. Assertion(A): Benzoic acid does not undergo Friedel Craft’s reaction.
Reason(R): Carboxyl group is deactivating and the catalyst aluminium chloride gets bonded to the carboxyl group.
ans. (a) Both A and R are true and R is the correct explanation of A
15. Assertion : D(+) Glucose is dextrorotatory in nature.
Reason : ‘D’ represents its dextrorotatory nature.
ans. (d) A is false but R is true
16. Assertion: Aniline does not give Friedel craft alkylation or Friedel Craft acylation reaction.
Reason: Aniline forms an salt with Lewis acid like AlCl3 which is deactivating in nature .
ans. (a) Both A and R are true and R is the correct explanation of A
SECTION – B
17. Calculate the mole fraction of benzene in a solution containing 30% by mass of it in CCl4.
18. Give the reactions, when:
(a) Glucose reacts with bromine water .
(b) Glucose is heated with HI for long time.
19. Explain pseudo-order reaction with an example.
20. (a)Define Glycosidic linkage.
(b) Why cannot vitamin C be stored in our body.
OR
(i) What type of linkage is present in nucleic acids?
(ii) Give one example each for fibrous protein and globular protein.
21. Explain why [Fe(H2O)6]3+ has a magnetic moment value of 5.92 BM whereas [Fe(CN)6]3- has a value
of only 1.74 BM.
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To download the complete question paper and its solutions, click on the link below:
CBSE Class 12 Chemistry Pre-Board Sample Paper 2025
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