PSEB CLASS 12 CHEMISTRY
September Exam Sample Paper 2025 – SET 2
Class: 10+2
Subject: Chemistry
Time Allowed: 3 Hrs
Maximum Marks: 70
Section – A
(1 mark each, 20×1 = 20 marks)
Q.1 Answer the following (MCQ, Fill in the blanks, True/False, Comprehensive):
-
Which concentration term involves volume of solution?
(a) Molarity (b) Molality (c) Mole fraction (d) None -
Which of the following shows positive deviation from Raoult’s law?
(a) Benzene + Toluene
(b) Acetone + Chloroform
(c) Ethanol + Water
(d) None -
If a solution has osmotic pressure 4.92 atm at 300K, concentration of solute is (R = 0.0821 L atm mol⁻¹ K⁻¹):
(a) 0.2M (b) 0.3M (c) 0.4M (d) 0.5M -
In which cell is Daniell cell used?
(a) Primary cell (b) Secondary cell (c) Fuel cell (d) None -
EMF of a cell depends on:
(a) Nature of reactants (b) Concentration of solution (c) Temperature (d) All of these -
Which of the following has unit s⁻¹?
(a) Zero-order rate constant
(b) First-order rate constant
(c) Second-order rate constant
(d) None -
The half-life of a first-order reaction is:
(a) Directly proportional to initial concentration
(b) Inversely proportional to initial concentration
(c) Independent of initial concentration
(d) None -
The rate of reaction doubles when concentration is doubled. The order of reaction is:
(a) Zero (b) One (c) Two (d) Three -
Which of the following is diamagnetic?
(a) Ti³⁺ (b) Zn²⁺ (c) Mn²⁺ (d) Cr³⁺ -
Which element shows maximum oxidation states?
(a) Mn (b) Fe (c) V (d) Co -
Which ion is colourless?
(a) Sc³⁺ (b) Ti³⁺ (c) Cr³⁺ (d) Mn²⁺ -
Which of the following is a hexadentate ligand?
(a) NH₃ (b) H₂O (c) EDTA (d) CN⁻ -
The coordination number of Co in [Co(NH₃)₆]³⁺ is:
(a) 4 (b) 5 (c) 6 (d) 8 -
Which of the following is a linkage isomer?
(a) [Co(NH₃)₅(NO₂)]Cl₂ and [Co(NH₃)₅(ONO)]Cl₂
(b) [Cu(NH₃)₄]SO₄ and Cu(NH₃)₄
(c) [Fe(CN)₆]³⁻ and [Fe(CN)₆]⁴⁻
(d) None -
Which of the following is a reducing sugar?
(a) Sucrose (b) Glucose (c) Cellulose (d) Starch -
DNA is a:
(a) Monosaccharide (b) Disaccharide (c) Polysaccharide (d) Nucleic acid -
Name the simplest monosaccharide.
-
Give one example of disaccharide.
-
True/False: Vapour pressure of solution is always higher than that of pure solvent.
-
True/False: Actinoids show greater tendency towards complex formation than lanthanoids.
Section – B
(2 marks each, 7×2 = 14 marks)
Q.2 Define mole fraction. Calculate mole fraction of ethanol in a solution containing 46 g ethanol and 180 g water.
Q.3 State Henry’s law. Give one application.
OR Which solution will have lower vapour pressure: 0.1 M NaCl or 0.1 M urea, and why?
Q.4 Define conductivity and molar conductivity.
Q.5 What is the effect of catalyst on rate of reaction and activation energy?
Q.6 Write electronic configuration of Cu and explain its stability.
OR Why does Cr²⁺ act as a reducing agent but Mn³⁺ as an oxidising agent?
Q.7 Define chelating ligands with one example.
Q.8 Differentiate between DNA and RNA (two points).
OR What are nucleosides and nucleotides?
Section – C
(3 marks each, 4×3 = 12 marks)
Q.9 Derive the relation between relative lowering of vapour pressure and mole fraction of solute.
OR Calculate mass of glucose required to be dissolved in 100 g of water to lower freezing point by 1.86 K. (Kf = 1.86 K kg mol⁻¹).
Q.10 Write the construction and working of hydrogen-oxygen fuel cell.
Q.11 Give reasons:
(a) Actinoids show wider range of oxidation states than lanthanoids.
(b) Lanthanoids show sharp spectral lines.
(c) Most of transition metals form coloured ions.
Q.12 Classify carbohydrates with examples.
Section – D
(5 marks each, 2×5 = 10 marks)
Q.13 Derive the integrated rate law for a zero-order reaction.
Q.14 (a) Write IUPAC names of the following coordination compounds:
(i) [Co(NH₃)₆]Cl₃
(ii) [Ni(CO)₄]
(iii) [Cr(H₂O)₄Cl₂]Cl
(b) Explain Werner’s theory of coordination compounds.
OR
(a) Write differences between double salts and coordination compounds.
(b) Write structure of [Ni(CN)₄]²⁻ using hybridisation concept.
