PSEB CLASS 12 CHEMISTRY
September Exam Sample Paper 2025
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):
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Which of the following is independent of temperature?
(a) Molarity (b) Molality (c) Normality (d) None -
Which of the following is an example of liquid-solid solution?
(a) Alloy (b) Amalgam (c) Adsorption (d) None -
The normality of 2M HNO₃ solution will be:
(a) 2 (b) 1 (c) 3 (d) 4 -
How many colligative properties are there?
(a) One (b) Two (c) Three (d) Four -
Which battery is used in inverters?
(a) Dry cell (b) Lead storage (c) Nickel-cadmium (d) None -
Which of the following is a primary cell?
(a) Dry cell (b) Mercury cell (c) Both (a) & (b) (d) None -
Units of resistance are:
(a) Ohm (b) Ohm cm⁻¹ (c) Ohm⁻¹ (d) None -
Units of zero order reaction are:
(a) mol L⁻¹ s⁻¹ (b) mol⁻¹ L s⁻¹ (c) s⁻¹ (d) None -
SOCl₂ → SO₂ + Cl₂ is an example of:
(a) First order (b) Second order (c) Zero order (d) None -
For which order reactions, order and molecularity are not equal?
(a) Zero order (b) First order (c) Second order (d) None -
Which orbitals have diffused shapes?
(a) s (b) p (c) d (d) f -
Which of the following shows exceptional configuration?
(a) Cu (b) Cr (c) Both (a) & (b) (d) Zn -
Which of the following has highest magnetic moment?
(a) Ni²⁺ (b) Cu²⁺ (c) Mn²⁺ (d) Co²⁺ -
Which of the following is colourless?
(a) Zn²⁺ (b) Cu⁺ (c) Sc³⁺ (d) All of these -
The ligand which has two donor sites is called:
(a) Monodentate (b) Bidentate (c) Polydentate (d) None -
The ion present outside the coordination sphere is called:
(a) Ligand (b) Central atom (c) Counter ion (d) None -
Write an example of homopolysaccharide.
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Glucose is a _____ (Monosaccharide/Disaccharide).
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True/False: Osmotic pressure is a colligative property.
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True/False: CN⁻ is an ambidentate ligand.
Section – B
(2 marks each, 7×2 = 14 marks)
Q.2 Which out of molarity and molality is affected by temperature and why?
Q.3 Concentrated H₂SO₄ has density 1.84 g/mL and is 98% by weight. Calculate molarity.
OR Which solution will be more concentrated, 1M or 1m, and why?
Q.4 Define ideal and non-ideal solution with example.
Q.5 Give one example of zero-order reaction.
Q.6 Differentiate between molecularity and order of reaction.
OR The rate constant for a first-order reaction is 60 s⁻¹. How much time will it take to reduce concentration to 1/10th of initial value?
Q.7 Why is Zn²⁺ not considered as a transition element?
Q.8 Define monodentate and bidentate ligands with one example each.
OR Name the coordination compound: Na[Au(CN)₂].
Section – C
(3 marks each, 4×3 = 12 marks)
Q.9 Differentiate between positive and negative deviations from Raoult’s law.
OR Calculate vapour pressure of an aqueous solution containing 5% urea (NH₂CONH₂) at 298K. (Vapour pressure of water = 23.75 mm Hg).
Q.10 Write the electrode reactions and working of a lead storage battery.
OR Write the Nernst equation and calculate emf of the cell:
Mg(s)/Mg²⁺(0.001) || Cu²⁺(0.001)/Cu(s).
(E° Mg²⁺/Mg = -2.37 V, E° Cu²⁺/Cu = 0.34 V).
Q.11 Why do transition elements form complexes?
Q.12 Write any three functions of carbohydrates in living systems.
Section – D
(5 marks each, 2×5 = 10 marks)
Q.13 Define first-order reaction. Derive an expression to show that time required for 99% completion is twice the time required for 90% completion.
Q.14 (a) What is lanthanoid contraction? Write its cause and consequences.
(b) Write the general electronic configuration of f-block elements.
OR
(a) Compare the chemistry of lanthanoids and actinoids.
(b) Name two elements which show +2 oxidation state.
