Class 11 PT II Question Paper 2025-26 Chemistry

CBSE CLASS 11
PT II Question Paper
Session 2025-26

CHEMISTRY

Exam CBSE Class 11
Subject Chemistry
Session 2025-26
Document Type PT II Question Paper

Notes · Sample Papers · Previous Year Papers · Mock Tests

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Question Paper
SECOND UNIT TEST
SESSION: 2025 – 2026 ag
CLASS: XI MAXIMUM MARKS: 40
SUBJECT: CHEMISTRY TIME: 1 HOUR 30 MINUTES
GENERAL INSTRUCTIONS:
Read the following instructions carefully and follow them:
1.� This question paper contains 18 questions and 03 pages. All questions are compulsory.

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2.� This question paper is divided into five sections – Section A, B, C, D and E

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3.� SECTION A – Question number 1 to 8 are multiple choice questions. Each question carries 1
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mark.
4.� SECTION B – Question number 9 to 11 are very short answer type questions. Each question
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carries 2 marks.

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5.� SECTION C – Question number 12 to 15 are short answer type questions. Each question carries 3

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marks.
6.� SECTION D – Question number 16 is case-based question and carries 4 marks.
7.� SECTION E – Question number 17 and 18 are long answer type questions. Each question carries
5 marks.
8.� There is no overall choice given in the question paper. However, an internal choice has been
provided in few questions in all the sections except section A and B.
9.� Use of log tables and calculator is not allowed.
SECTION – A

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Select and write the most appropriate option out of the four options given for each of the

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questions 1 - 8.

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1. The oxidation number of sulphur in H2SO5 is 1
(A) +3
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(B) +10

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(C) +7 (D) +6
2. Hyperconjugation is most useful for stabilizing which of the following carbocation? 1
(A) Neopentyl (B) Tert-butyl
(C) Iso-propyl (D) Ethyl
3. Nucleophilicity order is correctly represented by 1
(A) CH3– < NH2– < HO– < F– (B) CH3– > NH2– > HO– > F–
– – – –
(C) NH2 > F > HO > CH3 (D) CH3– ≃ NH2– > HO– ≃ F–
4. Match the terms mentioned in column I with the terms in column II. 1
Column (I) Column (II)

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(i) C6H5NH2 (p) -R effect

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(ii) CH(CH3)2 (q) +R effect

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(iii) C6H5NO2 (r) +I effect

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(iv) CH3CH2Cl (s) -I effect

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Choose the correct option:
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(C) (i−q), (ii−r), (iii−p), (iv−s)
(B) (i−s), (ii−p), (iii−r), (iv−q)
(D) (i−q), (ii−r), (iii−s), (iv−p)
5. Which of the following Newman’s projection of butane is most stable- 1

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(A) I (B) II

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(C) III (D) IV

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6. Which of the following is correct regarding the boiling point? 1
(A) n-Octane is greater than 2-methylheptane
(B) n-Octane is less than 2,2,3,3-tetramethylbutane
(C) n-Octane is equal to 2-methylheptane
(D) n-Octane is equal to 2,2,3,3-tetramethylbutane
Note: For question number 7 & 8 two statements are given – one labelled as Assertion (A)
and the other labelled as Reason (R). Select the correct answer to these questions from the
codes (A), (B), (C) and (D) as 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 and R is true
7. Assertion (A): In a reaction 1
Zn(s) + CuSO4 (aq) → ZnSO4(aq) + Cu(s)
Zn is a reductant but itself get oxidized.
Reason (R): In a redox reaction, oxidant is reduced by accepting electrons and reductant is
oxidized by losing electrons.
8. Assertion (A): Thiourea (NH2CSNH2) gives red color when its Lassaigne's extract is treated 1
with ferric chloride.
Reason (R): Compounds having N along with C gives red color when its Lassaigne's extract is
treated with ferric chloride.
SECTION – B
Questions 9 to 11 are very short answer questions carrying 2 marks each.
9. Manganate ion (MnO42-) undergoes disproportionation reaction in acidic medium, but 2
permanganate ion (MnO4-) does not. Why?
10. (a) Nitric acid added to sodium extract before adding silver nitrate for testing halogens. Give 2
reason
(b) What is the colour of Fe4[Fe(CN6)]3.xH2O ?
11. Why is Wurtz reaction not preferred for preparation of alkanes containing odd number of 2
carbon atoms? Illustrate your answer by taking one example.
SECTION – C
Questions numbers 12 to 15 are short questions carrying 3 marks each.
12. (a) Balance the following redox reaction using the ion-electron method (in acidic medium): 3
MnO4⁻ + C2O4 2- → Mn2+ + CO2
(b) Draw the structure of CrO5 and calculate the oxidation number of Cr in it.
13. Draw the resonance structure of Aniline and explain which one is the most stable and why? 3
OR
(a) Write the IUPAC name: - CH3COCH2CH2CH2COOH
(b) Write the structural formula of the following compound: 3-nitrocyclohexene
(c) Arrange the following as per the instruction given in bracket:
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� � [increasing order of stability]

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14. A hydrocarbon ‘X’ with molecular formula C6H12 decolourizes bromine water. It also shows 3
geometrical isomerism. When, hydrocarbon ‘X’ is treated with O3 and Zn/H2O, it forms ‘Y’
and ‘Z’. Out of these two product ‘Y’ is a ketone.
(a) Write down the name and formula of the compound ‘X’.
(b) Write down the structure and IUPAC name of ‘Y’ and ‘Z’.
15. (a) Give reason: 3
i.� Electromeric effect is temporary effect.
ii.� Hyperconjugation is called no bond resonance.
(b) An organic compound fused with sodium metal for testing nitrogen, halogens and
Sulphur in lassaigne’s test. Why?
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Section – D

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Questions numbers 16 is case based question carrying 4 marks.
16. Alkenes undergo addition reactions where it loses one pie bond to form two new sigma bonds 4
to add a reagent across the double bond. Symmetrical alkenes undergo an addition reaction and
form one dominant product. However, confusion arises when it is an unsymmetrical alkene.
The reagent can be added on either end of the double bond to form more than one product.
Markovnikov solved the regiochemistry dilemma in 1870 by proposing the Markovnikov Rule.
Few reagents such as Hydrogen Halides (HX), Sulfuric Acid (H2SO4), Alcohols (R-OH), and
Water (H2O) follow Markovnikov's Rule for the addition across the double bond of an
unsymmetrical alkene. However, HBr in the presence of a peroxide showed behaviour opposite

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to Markovnikov's rule of alkene addition thereby termed ‘The Anti-Markovnikov's Rule.’ The

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reaction was studied extensively by Morris Kharash and was explained in the paper titled: ‘The

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Addition of Hydrogen Bromide to Allyl Bromide' in 1933. As a tribute to his work, the Anti-

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Markovnikov rule is also known as the Kharasch effect. The reaction works only in the
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presence of peroxide; therefore, it is also called the ‘Peroxide effect.’

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Read the above passage and answer the following questions –
(a) Show the mechanism of formation of major and minor product when but-1-ene is reacted
with HBr in presence of benzoyl peroxide.
(b) ‘Peroxide effect is not observed in addition of HCl or HI to an alkene’- Justify the statement
with proper reason.
(c)Write down the structure and name of major product when water is added to 2-methyl
propene in presence of few drops of acid.
OR
(c) What are intermediates forms during addition of HX to alkene in absence of any peroxide?

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Section – E

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Questions numbers 17 and18 are long answer type questions carrying 5 marks each.

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17. (a) 0.3780 g of an organic compound gave 0.5740 g of silver chloride in Carius estimation. 5

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Calculate the percentage of chlorine in the compound.

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(b) Give reason:
i) Formic acid is a stronger acid than acetic acid.
ii) An allylic carbocation is more stable than tertiary carbocation.
iii) Ammonia is less basic than methyl amine.
OR
(a) Identify electrophilic centre in CH3CHO
(b) A mixture of three liquids A, B and C. there is a large difference in the boiling points of B
and rest of the two liquids i.e, A and C. Boiling point of liquids A and C are quite close. The
boiling point order of three liquids are B>A>C. Suggest the separating technic used for the

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separation of the liquids and mention which one separate at first and which one separate at last.

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(c) Will CCl4 give white precipitate of AgCl on heating it with AgNO3? Explain.

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18. (a) Carry out the following conversions: - 5

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(i) Benzene to acetophenone

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(b) Give the mechanism of nitration of Benzene.

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An alkyl halide C5H11Br(A) reacts with ethanolic KOH to give an alkene 'B', which reacts
with Br2 to give a compound 'C', which on dehydrobromination gives an alkyne 'D'. On
treatment with sodium metal in liquid ammonia, one mole of 'D' gives one mole of the sodium
salt of 'D' and half a mole of hydrogen gas. Complete hydrogenation of 'D' yields a straight
chain alkane.
(a) Identify A, B, C and D.
(b) Give the reactions involved.

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(c) Write the name and structure of the product when compound-A react with Aqueous-KOH

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