HBSE Class 12 Sample Paper 2024 Chemistry

HBSE
MODEL PAPER
2024
Practice Papers
MODEL PAPERS
Marking Scheme
ANSWER KEY

Sample Paper (2023-24)
Class 12th (Sr. Secondary) Code: CHE-856
Roll No.

Chemistry
(English Medium)
Academic / Open
[Time allowed: 3 hours] [Maximum Marks: 70]

General Instructions:-
Read the following instructions carefully and strictly follow them.
(i) This question paper is divided into five sections A, B, C, D and E.
(ii) This question paper contains 35 questions. All questions are compulsory.
(iii) In Section A – Question No. 1 to 18 are multiple choice (MCQ) type
questions carrying 1 mark each.
(iv) In Section B – Question No. 19 to 25 are very short answer (VSA) type
questions carrying 2 marks each.
(v) In Section C – Question No. 26 to 30 are short answer (SA) type
questions carrying 3 marks each.
(vi) In Section D – Question No. 31 and 32 are case based questions carrying
4 marks each.
(vii) In Section E – Question No. 33 to 35 are long answer (LA) type questions
carrying 5 marks each.
(viii) There is no overall choice. However an internal choice has been provided
in two questions in Section B, two questions in Section C, two questions
in Section D and two questions in Section E.
(ix) Use of calculators is not allowed.

SECTION-A
Question No. 1 to 18 are multiple choice (MCQ) type questions, carrying 1
mark each. (18x1=18)
1. The deficiency of which of the following Vitamins causes pernicious
anemia.
(a) Vitamin B1 (b) Vitamin B2
(c) Vitamin B6 (d) Vitamin B12
2. In comparison to 0.01 M solution of glucose, the depression in freezing point
of 0.01 M MgCl2 solution is
(a) the same (b) about twice
(c) about three times (d) about six times
3. Electrode potential for Cu electrode varies according to the equation.
0.0591 1
ECu2+/Cu=E°cu2+/cu – log
2 [𝐶𝑢2+]

The graph of E cu2+/cu vs log [cu2+] is
(a) (b)
ECu2+/Cu ECu2+/Cu

log[Cu2+]
log[Cu2+]

(b) (d)
ECu2+/Cu ECu2+/Cu

log[Cu2+] log[Cu2+]

4. For a first order reaction, the time taken to reduce the initial concentration by
1
a factor of th is 20 minutes. The time required to reduce initial
4
1
concentration by a factor of th is
16

(a) 20 min (b) 10 min
(c) 80 min (d) 40 min
5. Glucose on treatment with sodium amalgam gives.
(a) n-heptanoic acid (b) Sorbitol
(c) Gluconic acid (d) Glucaric acid

6. The reaction of chloroform with alcoholic KOH and p-toluidine forms.
(a) H3C NC (b) H3C CN
(c) H3C N2Cl (d) H3C NHCl2
7. When 1mol CrCl3.6H2O is treated with excess of AgNO3, 3 mol of AgCl are
obtained. The Formula of Complex is
(a) [CrCl3(H2O)3].3H2O (b) [CrCl3(H2O)4]Cl.2H2O
(c) [CrCl(H2O)5]Cl2.H2O (d) [Cr (H2O)6]Cl3
8. Monochlorination of toluene in sunlight followed by hydrolysis with
aqueous NaOH yield.
(a) o-cresol (b) m-cresol
(c) 2,4 – dihydroxy toluene (d) Benzyl alcohol
9. At PH=11, Cr2O72- ion changes to
(a) CrO3 (b) CrO42-
(c) Cr3+ (d) CrO22+
10. Ethanol on warming with Conc H2SO4 at 413 K gives
(a) Ethene (b) Diethyl ether
(c) Dimethyl ether (d) Ethyl hydrogen sulphate
11. Which of the following compound will dissolve in an alkali solution after it
undergoes reaction with Hinsberg's reagent.
(a) CH3 NH2 (b) (CH3)2 NH
(c) C6H5NHC6H5 (d) (CH3)3 N
12. The end product in the following sequence is
NaOH CO2 H+/H2O (CH3CO)2O
phenol A B C D
140°C
(a) Salicylic Acid (b) Salicylaldehyde
(c) Phenyl acetate (d) Aspirin
13. Aniline on oxidation with Na2Cr2O7 and H2SO4 gives
(a) Benzoic acid (b) m-amino benzoic acid
(c) Schiff's base (d) p-Benzoquinone

14. We are having three aqueous solutions of K2SO4 labelled as 'X', 'Y' and 'Z'
with the concentration of 0.001M, 0.01 M, 0.1 M respectively. The value of
Van't Hoff factor for these solutions will be in the order.
(a) ix< iy <iz (b) ix >iy> iz
(c) ix = iy = iz (d) ix < iy > iz
For Questions 15 to 18 two statements are given-one labeled 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 the 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): For CH3COOH the Molar conductance of 0.1 M CH3COOH
and equivalent conductance of 0.1 N CH3COOH is same.
Reason (R): These do not depend upon concentration.
16. Assertion (A): For an exothermic reaction activation energy for the
backward reaction is more than the activation energy of the
forward reaction.
Reason (R): If the activation energy is high, the reaction is slow.
17. Assertion (A): Lanthanoids show a limited number of oxidation states
where as Actinoids show a large number of oxidation states.
Reason (R): Energy gap between 4f, 5d and 6s subshell is small where
as that between 5f, 6d and 7s subshell in large.
18. Assertion (A): Aniline is more basic than ethylamine.
Reason (R): The lone pair on N atom is present in Conjugation with
benzene ring and becomes less available for protonation
because of resonance.

SECTION-B
19. Account for the following:-
(a) Aniline does not undergo Friedal craft reaction.
(b) Methylamine is water reacts with ferric chloride to precipitate hydrated
ferric oxide. (2x1=2)
20. Among the isomeric alkanes of molecular formula C 5H12, identify the one
which on photochemical chlorination yields
(a) a single monochloride
(b) four isomeric monochlorides (2x1=2)
OR
Explain:
(a) Why Grignard reagent should be prepared under anhydrous conditions.
(b) Why the dipole moment of chlorobenzene is lower than that of
cyclohexyl chloride. (2x1=2)
21. (a) Give one structural difference between amylase and amylopectin.
(b) What type of bonding helps in stabilising the -helix structure of
proteins. (2x1=2)
22. Draw all the isomers (geometrical and optical) of
[COCl2(en)2]+ (2)
23. How many electrons flow through a metallic wire if a current of 0.5A is
passed for 4 hours. (2)
24. (a) Explain the following through example
(i) Azeotropic mixture
(ii) Isotonic solutions (2x1=2)
OR
(b) Derive relationship between mole fraction and vapour pressure of
components of an ideal solution in liquid phase and vapour phase. (2)
25. What is the effect of adding a catalyst on
(i) Activation Energy (Ea) of the reaction
(ii) Gibbs free energy (G) of the reaction. (2x1=2)

SECTION-C
26. Define the following as related to protein
(a) Peptide linkage
(b) Denaturation
(c) Primary structure (3x1=3)
OR
How do you explain the amphoteric behaviour of amino acid. (3)
27. Give equations of the following reactions.
(a) Oxidation of propano1 with alkaline KMnO4 solution
(b) Bromine in CS2 with phenol
(c) Propanone with methyl magnesium bromide. (3x1=3)
28. For a certain chemical reaction, variation in the concentration, ln[R] vs
time(min) plot is shown below.

ln[R]

t(min)
For this reaction
(a) What is the order of reaction?
(b) What are the units of rate constant K for this reaction?
(c) Give the relationship between K and t½ of this reaction. (3x1=3)
29. Two elements A and B form compounds having formula AB2 and AB4 when
dissolved in 20gm of benzene (C6H6), 1 gm of AB2 lowers the freezing point
by 2.3K where as 1.0 gm of AB4 lowers it by 1.3K. The molal depression
constant for benzene is 5.1Kkg./mol. Calculate atomic masses of A and B.(3)
30. Write the product of the following reactions:-
H2NCONHNH2
(a) C6H5CHO
(b) O
[Ag(NH3)2]+
CHO

(c) CrO3 / H2SO4 (3x1=3)
OH

OR
Do the following conversions:-
(a) Ethanal to But-2-enal
(b) Benzaldehyde to 3-phenyl propan-l-ol
(c) Benzone acid to Benzaldehyde (3x1=3)
SECTION-D
The following questions are case based questions. Read the case carefully and
answer the questions that follow:-
31. One of the latest theory to explain bonding in coordination compounds is
crystal field theory which consider metal ligand bond to be ionic unlike
valence bond theory. It considers the effect of ligands on the relative energy
of d orbitals of the central metal atom/ion. In free transition metal ion, all the
d-orbitals are degenerate. However this degeneracy split in the presence of
ligands which may be anions or polar molecules like H2O, NH3 etc. The
pattern of splitting depends upon the nature of crystal field generated by the
ligands around the metal ion.
Answer the following questions:-
(a) What is the crystal field splitting energy? (1)
(b) Draw crystal field splitting diagram for Octahedral field. (2)
OR
(b) The hexaaqua manganese(II) ion contains five unpaired electrons while
the hexacyano ion contain only one unpaired electron. Explain using
crystal field theory. (2)
(c) How does the magnitude of o decide the actual configuration of d-
orbital in a coordination entity. (1)
32. Alkyl halides undergo two types of nucleophillic substitution reactions SN1
and SN2. SN1 reactions are two step reactions which proceed through the

formation of carbocation while SN2 are one step reactions proceed through
the formation of transition state.
Answer the following questions:-
(a) Out of C6H5CH2Cl and C6H5CHClC6H5 which is more easily hydrolysed
by aqueous KOH following SN1 mechanism. (1)
(b) Arrange the following compounds in the order of reactivity towards SN 2
displacement (1)
2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane
(c) Why allyl chloride is hydrolysed through SN1 mechanism. (1)
(d) Why 1-Jodobutane is more reactive than 1-Chlorobutane towards
nucleophilic substitution reaction. (1)
OR
heat
(d) + Br2 predict the product of this reaction. (1)
UV light
SECTION-E
33. (a) Describe the preparation of potassium dichromate from iron chromite
ore. Write reactions involved in the preparation. (3)
(b) Describe the oxidizing action of potassium dichromate on
i. Iodide ion
ii. Iron (II) solution.
Write Ionic equation for the reactions. (2)
OR
(a) Describe the preparation of potassium permanganate. (2)
(b) Compare the chemistry of actinoids with that of lanthanoids with special
reference to
i. Electronic Configuration
ii. Atomic and Ionic size
iii. Chemical reactivity (3)

34. (a) Write the Nernst equation and calculate emf of the following cells at
298K
Mg(s) | Mg2+(0.001M) || Cu2+(0.0001M)/Cu(s)
E°Mg2+/Mg -2.36V E° Cu2+/Cu 0.34V (3)
(b) Why does the conductivity of a solution decrease with dilution? (2)
OR
(a) Write the chemistry of recharging of the lead storage battery highlighting
all the material that are involved during recharging. (3)
(b) Can we store copper sulphate solution in a zinc pot? (2)
35. Write the structures of product of the following reactions:-
CH3
(a) (a) CrO2Cl2
(b) H3O+
NO2

CH2CH3
(b) KMnO4
KOH, heat

O

(c) + NH2OH

(d) HCHO + Conc. NaOH
Dil
(e) CH3CHO + CH3CH2CHO (5x1=5)
NaOH
OR
(a) Give chemical test to distinguish between phenol and benzoic acid. (1)
(b) Out of acetaldehyde and acetone which is more reactive towards
nucleophillic addition reaction and why? (1)
(c) An organic compound with the molecular formula C9H10O forms 214-
DNP derivative, reduces tollen's reagent and undergoes eannizaro
reaction. On vigorous oxidation it gives 1,2-benzene dicarboxylic acid.
Identify the compound. Write the reactions involved. (3)