Class 12 Sample Paper 2026 Chemistry

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FOR
CBSE BOARD
AND
STATE BOARDS

Annual Examination Practice Paper
Session: 2025-26
CLASS – XII
Chemistry (CODE :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. 1 mole of liquid A and 2 moles of liquid B make a solution having a total vapour
pressure 40 torr. The vapour pressure of pure A and pure B are 45 torr and 30 torr
respectively. The above solution
(a) is an ideal solution.
(b) shows positive deviation.
(c) shows negative deviation.
(d) is a maximum boiling azeotrope.

2. Standard electrode potential for Sn4+/Sn2+ couple is +0.15 V and that for the Cr3+/Cr
couple is —0.74 V. The two couples in their standard states are connected to make a
cell. The cell potential will be
(a)​+1.19 V​
(b)​+0.89 V
(c)​+0.18 V​
(d)​+1.83 V

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3. Out of Fe2+, Co2+, Cr3+, Ni2+, the one which shows lowest magnetic moment is :
(a) Fe2+
(b) Co2+
(c) Cr3+
(d) Ni2+

4. Which type of isomerism is shown by the given complex ?
[Co(en)3]3+
(a) Coordination isomerism
(b) Optical isomerism
(c) Linkage isomerism
(d) Ionisation isomerism
[Atomic number : Fe = 26, Co = 27, Ni = 28, Cr = 24]

5. Auto-oxidation of chloroform in air and light produces a poisonous gas known as
(a) Phosphine gas
(b) Mustard gas
(c) Phosgene gas
(d) Tear gas

6. The correct IUPAC name of (CH3)3 C – CH2Br is :
(a) 2,2-Dimethyl-2-bromopropane
(b) 1-Bromo-2,2,2-trimethylethane
(c) 2-Bromo-1,1,1-trimethylethane
(d) 1-Bromo-2,2-dimethylpropane

7. Williamson’s‍synthesis ‍of ‍preparing ‍dimethyl‍ether ‍is ‍a/an‍
(a) electrophilic substitution
(b) SN1 reaction
(c) electrophilic addition
(d) SN2 reaction

8. Which of the following alcohols will not undergo oxidation ?
(a) Butanol
(b) Butan-2-ol
(c) 2-Methylbutan-2-ol
(d) 3-Methylbutan-2-ol

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9. Which of the following does not undergo Aldol condensation ?
(a) HCHO
(b) CH3CH2CHO
(c) CH3COCH3
(d) CH3CHO

10. Which one of the following has the lowest pKa value ?
(a) CH3 – COOH
(b) O2N – CH2 – COOH
(c) Cl – CH2 – COOH
(d) HCOOH

11. Three compounds are given below :
(C2H5)3N, C2H5NH2, (C2H5)2NH
I II III
Identify the correct decreasing order of their basic strength in gas phase :
(a) II > III > I
(b) III > I > II
(c) III > II > I
(d) I > III > II

12. Nucleic acids are the polymers of :
(a) Nucleosides
(b) D-ribose
(c) Amino acids
(d) Nucleotides

For Questions number 15 to 18, 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 Assertion (A) and Reason (R) are true and Reason (R) is the correct
explanation of the Assertion (A).
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct
explanation of the Assertion (A).
(c) Assertion (A) is true, but Reason (R) is false.
(d) Assertion (A) is false, but Reason (R) is true.
15. Assertion (A) : Chloroform and acetone mixture shows negative deviation from
Raoult’s law.
Reason (R) : In chloroform and acetone mixture, A – A or B – B type intermolecular
interactions are weaker than A – B type interactions.

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16. Assertion (A) : Conductivity of an electrolyte increases with decrease in
concentration.
Reason (R) : Number of ions per unit volume decreases on dilution.

17. Assertion (A) : Glucose gets oxidised to six carbon carboxylic acid on reaction with
bromine water.
Reason (R) : Glucose contains a ketonic group.

18. Assertion (A) : Benzene diazonium salt is stable and can be easily stored.
Reason (R) : Benzene diazonium chloride decomposes easily.

SECTION-B

Directions (Q. Nos. 17-21) : This section contains 5 questions with internal choice in
one question. The following questions are very short answer type and carry 2 marks
each.

17. A non-volatile solute ‘X’ (molar mass = 50 g mol–1) when dissolved in 78g of
benzene reduced its vapour pressure to 90%. Calculate the mass of X dissolved in
the solution.

18. A first order reaction takes 40 min for 75 % decomposition. Calculate rate constant.
(log 2 = 0·30, log 4 = 0·60)

19. Give the IUPAC name and electronic configuration of central metal atom in terms of
t2g and eg of K4[Mn(CN)6].

20. Write the reaction involved in the following :
(a) Reimer-Tiemann reaction
(b) Kolbe’s‍reaction

21. (A) (a) Draw the zwitter ion structure for sulphanilic acid. 2 × 1 = 2
(b) How can the activating effect of –NH2 group in aniline be controlled ?
OR
(B) How will you carry out the following conversions :
(a) Ethanamide to Methanamine
(b) Ethanenitrile to Ethanamine

Page 4 of 8

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

22. Calculate elevation of the boiling point of the solution when 4 g of MgSO4 (molar
mass = 120 g/mol) was dissolved in 100 g of water, assuming MgSO4 undergoes
complete ionisation.
(Kb for water = 0.52 K kg mol–1)

23. Conductivity of 2 x 10–3 M methanoic acid is 8 x 10–5 S cm–1. Calculate its molar
conductivity and degree of dissociation if Λ°m for methanoic acid is 404 S cm2 mol–1.

24. (a) Which ion amongst the following is colourless and why ?
Ti4+, Cr3+, V3+
(Atomic number of Ti = 22, Cr = 24, V = 23)
(b) Why is Mn2+ much more resistant than Fe2+ towards oxidation ?
(c) The highest oxidation state of a metal is shown in its oxide or fluoride only.
Justify the statement.

25.
Metal Cr Mn Fe Co Ni Cu Zn

E°M2+/M -0.91 -1.18 -0.44 -0.28 -0.25 +0.34 -0.76

(a) Why is E°Mn2+/Mn value highly negative as compared to other elements ?
(b) What is the reason for the irregularity in the above E° values ?
(c) Why is E°Cu2+/Cu value exceptionally positive ?

26. Write chemical equations for the following :
(a) Reaction between phenol and Zn dust.
(b) Reaction of anisole with bromine in ethanoic acid.
(c) Reaction between methoxybenzene and HI.

27.(A) (a) Why do tertiary alkyl halides undergo SN1 reaction at a faster rate ?
(b) Define Enantiomers.
(c) Why is chloroform stored in dark coloured air tight bottles ? 1+1+1

OR

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(B) (a) Write the major alkene that would be formed by dehydrohalogenation of
2-Bromopentane.
(b) Which would undergo SN2 reaction at a faster rate and why ?
CH3CH2Br or (CH3)3Br
(c) Why is chlorobenzene less reactive towards nucleophilic substitution reaction ?

28. (a) Write the reaction involved in Cannizaro’s reaction.
(b) Give chemical tests to distinguish between the following pair of compounds :
(i) Propanal and Propanone
(ii) Benzaldehyde and Benzoic acid

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. Oxidation-reduction reactions are commonly known as redox reactions. In galvanic
cell, the chemical energy of a spontaneous redox reaction is converted into
electrical energy, whereas in an electrolytic cell, electrical energy is used to carry out
a non-spontaneous redox reaction. The standard electrode potential for any
electrode dipping in an appropriate solution is defined with respect to standard
electrode potential of hydrogen electrode taken as zero. Concentration dependence
of the potentials of the electrodes and the cells are given by Nernst equation.

Answer the following questions:
(a) Predict whether the reaction is spontaneous or non-spontaneous if E°cell is
positive ? 1
(b) When does a galvanic cell behave like an electrolytic cell ? 1
(c) Define the following terms : 2´1=2
(i) Redox reaction
(ii) Galvanic cell
OR
(c) Write cell reaction and Nernst equation for the following cell at 25°C : 2
Ni (s) | Ni2+ (aq) || Ag+ (aq) | Ag (s)

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30. In coordination compounds, metals show two types of linkages, primary and
secondary. Primary valencies are ionisable and are satisfied by negatively charged
ions. Secondary valencies are non-ionisable and are satisfied by neutral or negative
ions having lone pair of electrons. Primary valencies are non-directional while
secondary valencies decide the shape of the complexes.

Answer the following questions:
(a) If PtCl2. 2NH3 does not react with AgNO3, what will be its formula ? 1
(b) What is the secondary valency of [Co(en)2Cl2]+ ? 1
(c) (i) Write the formula of Iron(III)hexacyanidoferrate(II).
(ii) Write the IUPAC name of [Co(NH3)5Cl] Cl2. 2
OR
(c) Write the hybridization and magnetic behaviour of [Ni(CN)4]2- 2
[Atomic number : Ni = 28]

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.(A) (a) What happens to the rate constant k and activation energy Ea as the
temperature of a chemical reaction is increased ? Justify.
(b) The following data were obtained during the kinetic studies of the reaction :

A + 2B → C + 2D

Initial [A] Initial [B] Initial rate of
Experiment (mol/L) (mol/L) formation of C
(M min–1)

1 0.1 0.1 3 x x 10– 4

2 0.3 0.3 9.0 x 10– 4

3 0.1 0.3 3.0 x 10– 4

4 0.2 0.4 6.0 x 10– 4

Determine the order of reaction with respect to each reactant and the
overall order of the reaction. Write the rate law expression for the reaction.

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OR

(B) (a) Define pseudo first order reaction with one example.
(b) The rate constant of a first order reaction increases from 4 x 10–2 to 8 x 10–2
when the temperature changes from 27°C to 37°C. Calculate its energy of
activation (Ea).
(Given : 2.303 R = 19.15 JK–1 mol–1, log2 = 0.30)
2+3=5
32. (A) Compound A undergoes Rosenmund reduction to give compound B with
molecular formula C7H6O. Compound B does not give Fehling s test but reacts
with conc. NaOH to give C and D.
Identify A, B, C and D and write all the reactions involved.
Write one chemical test to distinguish between compound B and propanone.

OR

(B) Compound A with molecular formula (C2H6O) on oxidation by PCC gives
compound B, which on treatment with dilute alkali forms compound C which is a
𝛃-hydroxy aldehyde. B on oxidation by potassium permanganate forms C.
Identify A, B, C and D and write all the chemical equations involved.

33. (A) (a)Write the reaction of glucose with :
(i) HI
(ii) HNO3 (conc.)
(iii) HCN
(b) Give two differences between DNA and RNA.

OR

(B) (a) Name the linkage formed when carboxyl end of one amino acid condenses
with amino end of other amino acid.
(b) What are essential amino acids and non-essential amino acids ?
(c) (i) Why are the two strands of DNA complementary ?
(ii) What type of linkage joins two nucleotides ?

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