Class 11 Sample Paper 2026 Chemistry

2026
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PRACTICE PAPER (Class-11th)

Chemistry (043)
Time: 3 Hours Maximum Marks: 70

General Instructions:
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

Directions (Q. No. 1-16) : The following questions are multiple-choice questions with one correct
answer. Each question carries 1 mark. There is no internal choice in this section.

1. Which of the following contains the maximum number of atoms?
(Molar mass of He = 4 g, Na = 23 g, Ca = 40 g )
(A) 4 g He
(B) 46 g Na
(C) 0.40 moles of Ca
(D) 12 g He

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2. 5 moles of AB2 weighs 125 g and 10 moles of A2B2 weighs 300 g. The molar mass of A and B (in
g mol−1 ) respectively are:
(A) 10, 5
(B) 50, 25
(C) 25, 50
(D) 5, 10

3. The electrons, identified by quantum numbers n and l are-
(I) n = 4, l = 1, (II) n = 4, l = 0, (III) n = 3, l = 2, (IV) n = 3, l = l
the correct order of increasing energy, from the lowest to highest is-
(A) (IV) < (II) < (III) < (I)
(B) (II) < (IV) < (I) < (III)
(C) (I) < (III) < (II) < (IV)
(A) (III) < (I) < (IV) < (II)

4. Consider the following molecules:
(I) CO2 (II) H2O (III) BF3 (IV) NH3
Out of these, molecule(s) having sp3 hybridization of central atom is/are-
(A) I, II, III, IV
(B) I, II
(C) II, IV
(D) IV only

5. Which of the following molecule is paramagnetic having bond order two?
(A) C2
(B) N2
(C) O2
(D) F2

6. Given: C (graphite, s) + O2 (g) → CO2 (g) ; ∆rHo = –393.5 kJ mol-1

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CO (g) + ½ O2 (g) → CO2 (g) ; ∆rHo = –283.0 kJ mol-1
The enthalpy of following reaction will be:
C (graphite, s) + ½ O2 (g) → CO (g)
(A) –676.5 kJmol-1
(B) –110. 5 kJmol-1
(C) –196. 75 kJmol-1
(D) 110. 5 kJmol-1

7. For an isolated system,
(A) ∆U = 0, ∆S = 0
(B) ∆U = 0, ∆S > 0
(C) ∆U > 0, ∆S < 0
(D) ∆U < 0, ∆S = 0

8. The best suitable method (sequence of reactions) to convert benzene into p-Chlorotoluene is:
(A) 1. CH3Cl / anhydrous AlCl3 2. CH4 / H+
(B) 1. Cl2 / anhydrous AlCl3 2. CH3Cl / anhydrous AlCl3
(C) 1. CH3Cl / anhydrous AlCl3 2. Cl2 / anhydrous AlCl3
(D) 1. CH3Cl / H+ 2. conc. HCl

9. For the equilibrium,
2X (g) 2Y (s) + Z (g);
The equilibrium constant Kc for the reaction is 300 and enthalpy of reaction rH = -100 kJ/mol.
The equilibrium constant Kp for the reaction at 300 K will be-
(A) 9×104 R
(B) 300 R
(C) R
(D) 1/R
(R is universal gas constant)

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10. The major product formed in following reaction will be:

(A) 1-Methylcyclohexan-1-ol
(B) 2-Methylcyclohexan-1-ol
(C) 1-Methylcyclohex-2-ene
(D) 1-Methylcyclohexane

11. Oxidation state of Cr in Cr2O72– is:
(A) +2
(B) –2
(C) +6
(D) +7

12. Number of sigma(σ) bonds and pi(π) bonds in ethyne molecule is/are __ and __ respectively.
(A) 4, 1
(B) 1, 4
(C) 3, 2
(D) 1, 2

13. Assertion: Cyclopentadienyl anion is aromatic.
Reason: Cyclopentadienyl anion contains 6 π electrons.
(A) Both assertion and reason are correct and reason is correct explanation of assertion
(B) Both assertion and reason are correct but reason is not correct explanation of assertion
(C) Assertion is correct but reason is incorrect
(D) Assertion is incorrect but reason is correct

14. Assertion: Heat(q) and work(w) are not state function but q + w is state function.
Reason: Sum of heat and work gives ∆U.

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(A) Both assertion and reason are correct and reason is correct explanation of assertion
(B) Both assertion and reason are correct but reason is not correct explanation of assertion
(C) Assertion is correct but reason is incorrect
(D) Assertion is incorrect but reason is correct

15. Assertion: Halogens exhibits negative E° values.
Reason: Halogens have high electronegativity.
(A) Both assertion and reason are correct and reason is correct explanation of assertion
(B) Both assertion and reason are correct but reason is not correct explanation of assertion
(C) Assertion is correct but reason is incorrect
(D) Assertion is incorrect but reason is correct

16. Assertion: Chlorine has most negative electron gain enthalpy among halogens.
Reason: Chlorine has smallest size and highest electronegativity.
(A) Both assertion and reason are correct and reason is correct explanation of assertion
(B) Both assertion and reason are correct but reason is not correct explanation of assertion
(C) Assertion is correct but reason is incorrect
(D) Assertion is incorrect but reason is correct

SECTION-B

Directions (Q. Nos. 17-21) : This section contains 7 questions with internal choice in two questions.
The following questions are very short answer type and carry 2 marks each.

17. Explain positive resonance effect using suitable examples.
OR
Mention the principle involved in following purification techniques:
(i) Distillation
(ii) Chromatography

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18. Balance the following redox reaction in acidic medium:
MnO4– (aq) + C2O42– (aq) → Mn2+(aq) + CO2 (g)

19. (i) State law of multiple proportions.
(ii) How 0.5 mol Na2CO3 and 0.5 M Na2CO3 are different?

20. (i) Define isoelectronic species.
(ii) Write a cation and anion which is isoelectronic with Ar.

21. (i) State Le Chatelier principle.
(ii) Write conjugate acid and base of HCO3– ion.

SECTION-C

Directions (Q. Nos. 22-28) : This section contains 5 questions with internal choice in two questions.
The following questions are short answer type and carry 3 marks each.

22. A compound contains 4.07 % hydrogen, 24.27 % carbon and 71.65 % chlorine. Its molar mass is
98.96 g. What are its empirical and molecular formulas ?
(Molar mass of H = 1 g, C = 12 g, Cl = 35.5 g )

23. Define following terms:
(i) Closed system
(ii) Intensive property
(iii)Entropy

24. Name the period-2 element which has:
(i) lowest ionization enthalpy
(ii) positive electron gain enthalpy

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(iii) highest electronegativity

25. Calculate the energy associated with the first orbit of He+ . What is the radius of this orbit?

26. Write the IUPAC names of following:

OR
(i) Write IUPAC names of all chain isomers having molecular formula C5H10.
(ii) Identify the type of isomerism exhibited by Ethoxyethane and Methoxypropane.

27. For the reaction, 2A (g) + B (g) → D (g)
∆U° = –10.5 kJ, ∆S° = – 44 J K–1
Calculate ∆G° for the reaction, and predict whether the reaction may occur spontaneously.

28. Consider the following reactions:

(i) Write structures of X and Y.
(ii) Out of X and Y which have higher boiling point and why?

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SECTION-D

Directions (Q. Nos. 29-30) : The following questions are case-based questions. Each question has an
internal choice and carries 4 marks each.

29. In an organic reactions, the organic molecule (also referred as a substrate) reacts with an appropriate
attacking reagent and leads to the formation of one or more intermediate(s) and finally product(s).

Substrate is that reactant which supplies carbon to the new bond and the other reactant is called reagent.
If both the reactants supply carbon to the new bond then choice is arbitrary and in that case the molecule
on which attention is focused is called substrate. In such a reaction a covalent bond between two carbon
atoms or a carbon and some other atom is broken and a new bond is formed.

(i) Write the intermediate formed in chlorination of ethane.
(ii) Select the electrophile out of following:
H2O, NH3, NF3, BF3

(iii) Arrange following carbocation in increasing order of stability:
CH3CH2+, (CH3)2CH+, O2N-CH2CH2+

OR
Differentiate two types of bond cleavage giving example of each.

30. Hydronium ion concentration in molarity is more conveniently expressed on a logarithmic scale
known as the pH scale. The pH of a solution is defined as the negative logarithm to base 10 of the
activity (aH+) of hydrogen ion. In dilute solutions (< 0.01 M), activity of hydrogen ion (H+) is equal in
magnitude to molarity represented by [H+]. It should be noted that activity has no units and is defined as:

aH+ = [H+] / mol L–1
From the definition of pH, the following can be written,
pH = – log aH+ = – log {[H+] / mol L–1}

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(i) Give an example of salt formed by reaction of a strong acid and weak base.
(ii) Give example of basic buffer solution.
(iii) Calculate the pH of a 0.001 M NaOH solution.
OR
Explain common ion effect with appropriate example.

SECTION-E

Directions (Q. No. 31-33) : The following questions are long answer type and carry 5 marks each. All
questions have an internal choice.

31. (i) Complete the reactions by writing structures of A to F.

(ii) Explain Wurtz reaction with appropriate example. Why alkanes containing odd number of
carbon atoms cannot be synthesised by this reaction?

OR
(i) Write Friedel-Crafts alkylation reaction and explain its mechanism.
(ii) Write reactions for following conversions:
(a) Benzene to m-Nitroacetophenone
(b) Ethyne to Toluene

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32. (i) Write molecular orbital electronic configurations of N₂ molecule.
Calculate its bond order and comment on its magnetic behaviour.
(ii) Explain shapes of following molecules on the basis of VSEPR theory:
XeF4, ClF3, NH3
OR
(i) Explain following:
(a) NH3 has higher boiling point than PH3.
(b) He₂ molecule does not exist.
(c) BF3 molecule is non-polar.
(ii) Describe the hybridisation of sulphur in SF6 molecule.

33. (i) Identify the type of orbital whose surface boundary diagram is given below:

(ii) How many subshells are associated with n = 3?
(iii) Write the electronic configuration of Cr (Z=24). Why is it different from the expected
configuration?
(iv) What will be the wavelength of a ball of mass 100 g moving with a velocity of 10 m s –1 ?

OR
(i) State Aufbau principle.
(ii) Mention one difference between principal quantum number (n) and azimuthal quantum
number (l).
(iii) A golf ball has a mass of 40g, and a speed of 45 m/s. If the speed can be measured within
accuracy of 2%, calculate the uncertainty in the position.
(Given: h = 6.626×10–34 J s)

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