IInd PUC Chemistry Solved Sample Paper 2026

GOVERNEMENT OF KARNATAKA
KARNATAKA SCHOOL EXAMINATION AND ASSEMENT BOARD
2025-26 II PUC MODEL QUESTION PAPER- 2

Subject: Chemistry (34)
Maximum Marks: 70
Time: 3.00 Hours
No. of Questions: 46

PART – A I. Select the correct option from the given choices. 15 × 1 = 15

1. The mass percentage (w/w) of glucose in water is 10% means:
   (a) 10 g of glucose dissolved in 100 g of water
   (b) 10 g of glucose dissolved in 90 mL of water
   (c) 10 g of glucose dissolved in 100 mL of water
   (d) 10 g of glucose dissolved in 90 g of water (Correct)
2. Which of the following elements is liquid at normal temperature?
   (a) Zinc
   (b) Mercury (Correct)
   (c) Aluminum
   (d) Water
3. The reagent used in Sandmeyer's reaction is:
   (a) N₂ gas
   (b) Cu and HCl
   (c) Cu₂Cl₂ and HCl (Correct)
   (d) CuCl₂
4. The main natural source of acetic acid is:
   (a) Milk
   (b) Vinegar (Correct)
   (c) Red ant
   (d) Butter
5. The reaction of aniline which produces zwitter ion as a major product is:
   (a) Direct nitration
   (b) Bromination
   (c) Sulphonation (Correct)
   (d) Friedel-Craft alkylation
6. The method used for separation of isomeric products obtained when phenol reacts with dilute HNO₃ at low temperature is:
   (a) Steam distillation (Correct)
   (b) Sublimation
   (c) Electrolysis
   (d) Solidification
7. The ligand which forms more stable coordination complexes is:
   (a) NH₃
   (b) CO₃²⁻
   (c) CN⁻ (Correct)
   (d) H₂O
8. Which of the following groups when present at para position increases the basic strength of aniline?
   (a) -NO₂
   (b) -Br
   (c) -NH₂ (Correct)
   (d) -COOH
9. In the following acids, vitamin is:
   (a) Ascorbic acid (Correct)
   (b) Adipic acid
   (c) Aspartic acid
   (d) Saccharic acid
10. The best reagent useful for separation and purification of aldehyde from ketone is
    (a) Tollens’ reagent
    (b) Sodium hydrogen sulphite
    (c) Sodium sulphate
    (d) 2,4-DNP reagent (Correct)
11. Statement–1: If on mixing the two liquids, the solution becomes hot, it implies that it shows negative deviation from Raoult's law.
    Statement–2: Solutions which show negative deviation are accompanied by decrease in volume.
    (a) Both Statement–1 and Statement–2 are true.
    (b) Statement–1 is true but Statement–2 is false. (Correct)
    (c) Both Statement–1 and Statement–2 are false.
    (d) Statement–1 is false but Statement–2 is true.
12. Match the following transition metal/compounds with their catalytic activity in the corresponding processes.

    Transition metal/compounds	Name of the process
    (i) TiCl4 + (Al(CH3)3)	(A) Wacker process
    (ii) PdCl2	(B) Contact process
    (iii) Ni	(C) Manufacture of polyethene
    (iv) V2O5	(D) Hydrogenation of fat

    (a) i-C, ii-A, iii-D, iv-B (Correct)
    (b) i-C, ii-A, iii-D, iv-B
    (c) i-A, ii-C, iii-D, iv-B
    (d) i-D, ii-A, iii-B, iv-C
13. Cumene hydroperoxide on hydrolysis with dilute acids gives
    (a) Phenol and oxygen
    (b) Phenol and hydrogen
    (c) Hydrogen and oxygen
    (d) Phenol and acetone (Correct)
14. Among the following cells, the cell used in the Apollo space program for providing electric power is
    (a) SHE
    (b) H₂-O₂ fuel cell (Correct)
    (c) Daniel cell
    (d) Mercury cell
15. The following results have been obtained during kinetic studies of the reaction A(aq) + 2B(aq) → C(aq). Choose the correct option for the rate equation.

    Experiment	[A] (mol L1−)	[B] (mol L1−)	Rate (mol L1− min1−)
    I	0.1	0.1	6.0 × 103−
    II	0.2	0.3	7.2 × 102−
    III	0.1	0.4	2.4 × 102−
    IV	0.4	0.3	2.88 × 101−

    (a) Rate = K [A]¹ [B]²
    (b) Rate = K [A]¹ [B]²
    (c) Rate = K [A]² [B]¹ (Correct)
    (d) Rate = K [A]⁴ [B]¹

PART – A II. Fill in the blanks by choosing the appropriate word from those given in the brackets:
[soft, hard, chloroform, three, nucleotide, two] 5 × 1 = 5

16. The polyhalo compound used as an aesthetic during surgery was chloroform.
17. Nucleic acids are the long chain polymers of nucleotide.
18. Van’t Hoff factor for KCl solution assuming the complete dissociation is two.
19. The number of hydroxyl groups present in glycerol is three.
20. Transition metals are known to make interstitial compounds. Formation of interstitial compounds makes the transition metal more hard.

PART – B III. Answer any three of the following. Each question carries 2 marks. (3 × 2 = 6)

21. What is Lucas reagent? Which class of alcohol produces turbidity immediately with it?

Lucas reagent is a mixture of anhydrous zinc chloride (ZnCl₂) dissolved in concentrated hydrochloric acid (HCl).
Tertiary alcohols (3° alcohols) produce turbidity immediately with Lucas reagent at room temperature.

22. Write the SN₂ mechanism for conversion of chloromethane to methanol.

The conversion of chloromethane (CH₃Cl) to methanol (CH₃OH) occurs via the SN₂ mechanism using hydroxide ion (OH⁻) as the nucleophile.

The reaction is:
CH₃Cl + OH⁻ → CH₃OH + Cl⁻

Mechanism (concerted, single-step with backside attack):
The nucleophile OH⁻ attacks the carbon atom from the side opposite to the leaving group (Cl), forming a pentacoordinate transition state, followed by departure of Cl⁻.

Transition state:

        δ⁻         δ⁻
        HO ··· CH3 ··· Cl
        

This results in inversion of configuration (though not observable in this case) and second-order kinetics.

23. For the reaction: H₂ (g) + I₂ (g) → 2HI (g); draw the diagram showing plot of potential energy versus reaction coordinate to explain the role of activated complex in a reaction.

The potential energy diagram for the reaction H₂ + I₂ → 2HI is shown below (the reaction is slightly exothermic):

Potential Energy
↑
|
|            Transition State
|          (Activated Complex)
|                  |
|                 | |                  
|                |   |
|               |     |
|              |       |
|             |         |
|-------------           ----------------
|     Reactant           Product 
|      H2 + I2              2HI
|
|_________________________________________
            Reaction Coordinate

The curve starts at the energy level of reactants, rises to a maximum (activated complex or transition state), then falls to the lower energy level of products.

Role of activated complex: It is the high-energy, unstable intermediate state where bonds are partially broken (H-H and I-I) and partially formed (H-I). It represents the energy barrier (activation energy) that must be overcome for the reaction to proceed. Molecules must collide with sufficient energy to reach this state before forming products.

24. Name the hormone released rapidly due to rise in blood glucose level to keep the blood glucose level within the narrow limit. Mention the number of amino acids present in this hormone.

The hormone is insulin.
Human insulin contains 51 amino acids (A chain: 21 amino acids; B chain: 30 amino acids, linked by disulfide bonds).

25. What are transition elements? Give an example.

Transition elements are the d-block elements (groups 3 to 12 in the periodic table) whose atoms have partially filled d subshells or which form cations with incomplete d subshells. They exhibit variable oxidation states, form coloured compounds, and act as good catalysts.
Example: Iron (Fe).

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