PSEB CLASS 11 CHEMISTRY GUESS PAPER MARCH 2026 SET 2

P.S.E.B. Guess Paper for 2025-26 (Set 2)

Class 11th (10+1)

Subject: Chemistry

Time: 3 Hours                                                                                         Max. Marks: 70

General Instructions:

1. There is one theory paper comprising 21 questions. All questions are compulsory.
2. Question No. 1 has 20 sub-parts carrying 1 mark each. This question contains multiple-choice, true/false, and comprehension-based questions.
3. Question No. 2 to 15 are of 2 marks each. There is an internal choice in four questions.
4. Question No. 16 to 19 are of 3 marks each. There is an internal choice in two questions.
5. Question No. 20 and 21 are of 5 marks each. There is an internal choice in both of them.

SECTION A (1 Mark Each)

Q1. Answer the following questions (i to xx):

Choose the correct answer (MCQs):

(i) What is the molar mass of 0.1 mole of glucose (C₆H₁₂O₆)?

• A) 16 g/mol
• B) 18 g/mol
• C) 20 g/mol
• D) 22 g/mol

(ii) The number of spherical nodes for 4d orbital is:

• (a) zero
• (b) one
• (c) two
• (d) three

(iii) Elements do emit radiation on their own and this property is known as _____:

• a) Radioactivity
• b) Refraction
• c) Absorption
• d) Adsorption

(iv) An element with positive electron gain enthalpy is:

• a. O
• b. Cl
• c. Na
• d. Ne

(v) Which one of the following has the shortest carbon bond length?

• a. Benzene
• b. Ethene
• c. Ethyne
• d. Ethane

(vi) An open system allows the transfer of:

• a. Only mass
• b. Only energy
• c. Both mass and energy
• d. Neither mass nor energy

(vii) Which of the following salts will give highest pH in water?

• (a) Na₂CO₃
• (b) CuSO₄
• (c) KCl
• (d) NaCl

(viii) Which of the following is a redox reaction?

• (a) NaCl + KNO₃ → NaNO₃ + KCl
• (b) Mg(OH)₂ + 2NH₄Cl → MgCl₂ + 2NH₄OH
• (c) CaC₂O₄ + 2HCl → CaCl₂ + H₂C₂O₄
• (d) 2Zn + 2AgCN → 2Ag + Zn(CN)₂

(ix) Which of the following is NOT a characteristic of organic compounds?

• A) Primarily composed of carbon and hydrogen
• B) Forms covalent bonds
• C) Always soluble in water
• D) Can exist in various physical states

(x) The alkane that yields two isomeric monobromo derivatives is?

• a) Neopentane
• b) Ethane
• c) Methane
• d) Propane

State True or False:

(xi) Isobars are those elements that have a different atomic number but the same mass number.

(xii) A reversible process is a process in which direction may be reversed at any stage by small change in variable like temperature, pressure.

(xiii) s-block elements are soft, highly reactive, do not show variable oxidation states.

(xiv) The angle between the overlapping of one s-orbital and p-orbital is 180°.

(xv) An oxidizing agent is a substance which reduces the other.

Read the passage and answer the questions (xvi to xx):

The s-Block Elements: The elements of Group 1 (alkali metals) and Group 2 (alkaline earth metals) which have ns¹ and ns² outermost electronic configuration belong to the s-Block Elements. They are all reactive metals with low ionization enthalpies. They lose the outermost electron(s) readily to form 1+ ion (in the case of alkali metals) or 2+ ion (in the case of alkaline earth metals). The metallic character and the reactivity increase as we go down the group. Because of high reactivity they are never found pure in nature. The compounds of the s-block elements, with the exception of those of lithium and beryllium are predominantly ionic.

(xvi) Which groups of the periodic table constitute the s-Block elements?

(xvii) What is the outermost electronic configuration of s-Block elements?

(xviii) Why are s-block elements never found pure in nature?

(xix) How does the metallic character of these elements vary down the group?

(xx) Name the two elements of the s-block whose compounds are an exception and are not predominantly ionic.

SECTION B (2 Marks Each)

Q2. What are colligative properties? List two examples.

OR

What is the difference between empirical and molecular formulas?

Q3. Name the scientist who first formulated the atomic structure.

Q4. What is the difference between an element and a compound?

Q5. Define Quantum Number?

Q6. Arrange the elements of second period in increasing order of first ionisation enthalpy.

OR

What are representative elements?

Q7. Why sodium chloride is a solid where as carbon tetrachloride is a liquid?

Q8. Draw molecular orbital energy level diagram for nitrogen molecule.

Q9. Differentiate between heat capacity or specific heat capacity?

Q10. What do you mean by Thermochemical equations?

OR

Under what conditions ΔH is equal to ΔU?

Q11. Define oxidation and reduction in terms of electrons.

Q12. Give difference between electrochemical and electrolytic cell.

Q13. What is the difference between an organic and inorganic compound? Give two distinguishing features.

Q14. Wurtz reaction cannot be used for the preparation of unsymmetrical alkanes. Give reasons.

OR

Melting point of cis-but-2-ene is lower than that of trans-but-2-ene. Give reason.

Q15. What are the necessary conditions for any system to be aromatic?

SECTION C (3 Marks Each)

Q16. Explain the law of conservation of mass with an example.

Q17. State and explain the Dalton’s Atomic Theory.

OR

Calculate the maximum work obtained when 0.75 mol of an ideal gas expands isothermally and reversible at 27°C from a volume of 15 L to 25 L.

Q18. Discuss the shape of following molecules using the VSEPR model: BeCl₂, BCl₃, SiCl₄, AsF₃, H₂S, PH₃.

Q19. For a reaction NH₄COONH₂ (g) ⇌ 2NH₃ (g) + CO₂(g). If equilibrium pressure is 3atm. Find the value of Kp.

OR

Explain the effect of change in concentration and change in pressure at equilibrium using Le- Chatelier’s principle.

SECTION D (5 Marks Each)

Q20. What is the photoelectric effect? State the result of a photoelectric effect experiment that could not be explained on the basis of laws of classical physics. Explain this effect on the basis of quantum theory of electromagnetic radiation.

OR

The lattice enthalpy of an ionic compound is the enthalpy when one mole of an ionic compound present in its gaseous state, dissociates into its ions. It is impossible to determine it directly by experiment. Suggest and explain an indirect method to measure lattice enthalpy of NaCl(s).

Q21. Elaborate on the principles of organic reaction mechanisms:
- Types of organic reactions
- Mechanism of nucleophilic and electrophilic substitution
- Factors affecting reaction rates
- Role of intermediates in organic reactions
- Energy profile of chemical reactions

OR

Explain the process of cracking of hydrocarbons. Describe the industrial significance of cracking in petroleum refining.