JOY AND CAMPION SR. SEC. SCHOOL SAGAR (M.P.

)
PT-3 (2024-25)
SUBJECT- Chemistry
TIME:3HR. CLASS- 12th MM:70

General Instructions :
Read the following instructions carefully and follow them :
(i) This question paper contains 33 questions. All questions are compulsory.
(ii) This question paper is divided into five sections – Section A, B, C, D and E.
(iii) Section A – questions number 1 to 16 are multiple choice type questions. Each question
carries 1 mark.
(iv) Section B – questions number 17 to 21 are very short answer type questions. Each
question carries 2 marks.
(v) Section C – questions number 22 to 28 are short answer type questions. Each question
carries 3 marks.
(vi) Section D – questions number 29 and 30 are case-based questions. Each question
carries 4 marks.
(vii) Section E – questions number 31 to 33 are long answer type questions. Each question
carries 5 marks.
(viii) 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.
(ix) Kindly note that there is a separate question paper for Visually Impaired candidates.
(x) Use of calculators is not allowed.

SECTION A
Questions no. 1 to 16 are Multiple Choice type Questions, carrying 1 mark each. 161=16
Q1. The standard electrode potential for Ni2+/Ni couple is – 0.25 V and for Ag+/Ag
couple is 0.80 V. These two couples are connected to make an electrochemical cell. The redox
reaction is spontaneous. The cell potential will be :
(A) + 1.05 V (B) – 1.05 V (C) + 0.55 V (D) – 0.55 V
Q2. Out of Fe2+, Co2+, Cr3+, Ni2+, the one which shows lowest magnetic moment is :
(A) Fe2+ (B) Co2+ (C) Cr3+ (D) Ni2+
[Atomic number : Fe = 26, Co = 27, Ni = 28, Cr = 24]
Q3. The geometry of paramagnetic nickel complex [NiCl4]2 – is :
(A) tetrahedral (B) octahedral (C) square planar (D) distorted octahedral
Q4. Which of the following does not undergo Aldol condensation ?
(A) HCHO (B) CH3CH2CHO (C) CH3COCH3 (D) CH3CHO
Q5. The IUPAC name of the complex [Co(NH3)5(ONO)]Cl2 is :
(A) Pentaamminenitrito-O-cobalt(III) chloride (B) Pentaamminenitrito-N-cobalt(III) chloride
(C) Pentaamminenitro-cobalt(III) chloride (D) Pentaamminenitrito-cobalt(II) chloride
Q6. The most stable complex among the following is :
(A) [Pt(NH3)2Cl2] (B) [Ag(NH3)2]Cl (C) [Pt(en)2Cl2]2+ (D) K4 [Fe(CN)6]

Q7. If amines are arranged in increasing order of their basic strength in gaseous phase, then the
correct order will be :
(A) NH3 < CH3NH2 < (CH3)3N < (CH3)2NH (B) NH3 < (CH3)2NH < (CH3)3N < CH3NH2
(C) (CH3)3N < (CH3)2NH < CH3NH2 < NH3 (D) NH3 < CH3NH2 < (CH3)2NH < (CH3)3N
Q8. The chemical test which can be used to distinguish between ethanamine and aniline is :
(A) Haloform test (B) Tollens’ test (C) Azo dye test (D) Hinsberg test
Q9. 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
Q10. Considering the strength of the ligand, the highest excitation energy will be observed in :
(A) [Co(H2O)6]3+ (B) [Co(NH3)6]3+ (C) [Co(CN)6]3– (D) [CoCl6]3–

Q11. For a chemical reaction, A B, it was observed that the rate of reaction doubles when the
concentration of A is increased four times. The order of the reaction is :
(A) 2 (B) 1 (C) ½ (D) Zero
Q12. Williamson’s synthesis of preparing dimethyl ether is a/an
(A) electrophilic substitution (B) SN1 reaction
(C) electrophilic addition (D) SN2 reaction

For Questions number 13 to 16, 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.
Q13. Assertion (A) : Rate constant increases with increase in temperature.
Reason (R) : Increasing the temperature of the substance increases the fraction of molecules,
which collide with energies greater than activation energy.
Q14. Assertion (A) : Cu2+ iodide is known.
Reason (R) : Cu2+ has strong tendency to oxidise I– to Iodine.
Q15. Assertion (A) : Maltose is a non-reducing sugar.
Reason (R) : Maltose is composed of two glucose units in which C-1 of one glucose unit is linked to
C-4 of another glucose unit.

Q16. Assertion (A) : Acetanilide is more basic than aniline.

Reason (R) : Acetylation of aniline results in decrease of electron density on nitrogen.
SECTION- B
Q17. (a) Account for the following : 1+1=2
(i) CH3CHO is more reactive than CH3COCH3 towards reaction with HCN.
(ii) Carboxylic acids are higher boiling liquids than aldehydes and ketones.
OR
(b) Give chemical tests to distinguish between the following pair of compounds : 1+1=2
(i) Propanal and Propanone
(ii) Benzaldehyde and Benzoic acid

Q18. Write the reaction involved in the following : 1+1=2

(a) Reimer-Tiemann reaction (b) Kolbe’s reaction

Q19. Write the reaction of glucose with : 1+1=2

(a) HI (b) Br2 water

Q20. The thermal decomposition of an acid is a first order reaction with a rate constant of 2.3 10–3 s–1
at a certain temperature. Calculate how long it will take for three-fourths of the initial quantity of
acid to decompose.
(log 4 = 0.6021, log 2 = 0.301) 2
Q21. Draw the structures of major monohalo products in each of the followingreactions : 2

SECTION C
Q22. Give plausible explanation for the following : 1+1+1=3
(a) Diazonium salts of aromatic amines are stable.
(b) Aniline does not undergo Friedel-Crafts reaction.
(c) Aniline on nitration gives a substantial amount of meta product.
Q23. Account for the following : 1+1+1=3
(a) The dipole moment of chlorobenzene is lower than that of cyclohexylchloride.
(b) Alkyl halides are immiscible in water.
(c) t-butyl bromide has lower boiling point than n-butyl bromide.

Q24. (a) Draw the geometrical isomers of the complex [Pt(NH3)2Cl2].

(b) Give the electronic configuration of d4 ion when Do > P.
(c) Solution of [Ni(H2O)6]2+ is green in colour whereas [Ni(CN)4]2– is colourless. Give reason.
[Atomic number : Ni = 28]
Q25. The electrical resistance of a column of 0.05 M NaOH solution of cell constant 50 cm–1 is 4.5 103
ohm. Calculate its resistivity, conductivity and molar conductivity. 3
Q26. 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) 3
Q27. Hydrolysis of ethyl ethanoate takes place by the chemical reaction :

Based on the above reaction, write : 3

(a) What do you call such reactions ?
(b) Rate law equation
(c) Molecularity and order of reaction

Q28. What happens when : (any three) 31=3

(a) is treated with CH3CHO followed by hydrolysis.

(b) Phenol is treated with conc. (HNO3 + H2SO4).

(c) Anisole is treated with CH3COCl in the presence of anhydrous AlCl3.

(d) Propan-2-ol is heated with Cu at 573 K.

SECTION- D
The following questions are case-based questions. Read the case carefully and answer the questions
that follow.
Q29. The particles in the nucleus of the cell, responsible for heredity, are called chromosomes which
are made up of proteins and another type of biomolecules called nucleic acids. These are mainly
of two types, DNA and RNA. Nucleic acids on hydrolysis yield a pentose sugar, phosphoric acid
and nitrogen containing heterocyclic compound. Nucleic acids have a very diverse set of
functions, such as cell creation, the storage and processing of genetic information, protein
synthesis and the generation of energy cells. Although their functions may differ, the structure of
 DNA and RNA are very similar, with only a few fundamental differences in their molecular make-
up.
Based on the above passage, answer the following questions :
(a) Write three types of RNA molecules. 1
(b) What products will be formed when a nucleotide from DNA containing thymine is hydrolysed ?
(c) (i) Give two differences between DNA and RNA. 2
OR
(c) (ii) (I) Why are the two strands of DNA complementary ? 1
(II) What type of linkage joins two nucleotides ? 1
30. The cause for deviation from Raoult’s law in the colligative properties of non-ideal solutions lie in
the nature of interactions at the molecular level. These properties show deviations from Raoult’s
law due to difference in interactions between solute – solvent, solute – solute and solvent –
solvent. Some liquids on mixing, form azeotropes which are binary mixtures having the same
composition in liquid and vapour phase and boil at a constant temperature. In such cases, it is not
possible to separate the components by fractional distillation. There are two types of azeotropes
called minimum boiling azeotrope and maximum boiling azeotrope.
Based on the above passage, answer the following questions :
(a) Pure ethanol cannot be prepared by fractional distillation of ethanol – water mixture
Comment. 1
(b) Why does a mixture of chloroform and acetone show deviation from ideal behaviour ? 1
(c) (i) The vapour pressure of pure benzene at a certain temperature is 1.25 atm.
When 1.2 g of non-volatile, non-electrolyte solute is added to 60 g of benzene (M = 78 g
mol–1), the vapour pressure of the solution becomes 1.237 atm. Calculate the molar
mass of the nonvolatile solute. 2
OR
(c) (ii) The boiling point of benzene is 353.23 K. When 1.80 g of a nonvolatile solute was
dissolved in 90 g of benzene, the boiling point is raised to 354.11 K. Calculate the
molar mass of the solute. Kb for benzene is 2.53 K kg mol–1.
SECTION- E
31. (a) (i) What type of battery is the lead storage battery ? Write the anode and the cathode 3
reactions and the overall reaction occurring in a lead storage battery when current is
drawn from it.
(ii) Calculate the time to deposit 1.5 g of silver at cathode when a current of 1.5 A was passed
through the solution of AgNO3.
[Molar mass of Ag = 108 g mol–1, 1 F = 96500 C mol–1] 2
OR
(b) (i) State Kohlrausch’s law of independent migration of ions. Molar conductivity at infinite dilution
for NH4Cl, NaOH and NaCl solution at 298 K are 110, 100 and 105 S cm2 mol–1 respectively.
Calculate the molar conductivity of NH4OH solution.

(ii) Calulate G° of the following cell at 25°C : 2

Q32. (a) (i) Explain with the help of chemical reaction when : 3
(I) Acetone is treated with semicarbazide.
(II) Two molecules of benzaldehyde are treated with conc. NaOH.
(III) Butan-2-one is treated with Zn/Hg and conc. HCl.
(ii) Arrange the following in the increasing order of their acidic strength : 2

b) (i) Identify the products A, B, C and D in the following sequence of reactions : 2

(ii) How will you bring about the following conversions ? 31=3
(I) Propanone to Propene
(II) Benzoic acid to Benzaldehyde
(III) Ethanal to But-2-enal
Q33. Attempt any five of the following : 51=5
(a) Cu+ is not stable in aqueous solution. Comment.
(b) Out of Cr2+ and Fe2+, which one is a stronger reducing agent and why ?
(c) Actinoid contraction is greater from element to element than lanthanoid contraction. Why ?
(d) KMnO4 acts as an oxidising agent in acidic medium. Write the ionic equation to support this.
(e) Name the metal in the first transition series which exhibits +1 oxidation state most frequently.
(f) Transition metals and their compounds are good catalysts. Justify.
(g) Scandium forms no coloured ions, yet it is regarded as a transition element. Why ?