PSEB CLASS 12 – CHEMISTRY
GUESS QUESTION PAPER 2026
Time: 3 Hours
Maximum Marks: 70
INSTRUCTIONS
All questions are compulsory.
QUESTION – 1
(Each question carries 1 mark)
Choose the correct answer:
(i) An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because
a. It gains water due to osmosis.
b. It loses water due to osmosis.
c. It gains water due to reverse osmosis.
d. It loses water due to reverse osmosis.
(ii) In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl₂ solution is?
a. The same
b. About twice
c. About three times
d. About six times
(iii) a-Isotonic solution have
a. same boiling point
b. same vapour pressure
c. same melting point
d. same osmotic pressure
(iv) The unit of cell constant is
a. cm⁻¹
b. cm²
c. cm
d. S cm²
(v) In Bimolecular reaction if one of the reactants is in excess it is called
a. Pseudo First order
b. Zero Order
c. Second Order
d. Third Order
(vi) The coordination number of platinum in [PtCl₂(C₅H₅N)(NH₃)] is
a. 3
b. 4
c. 5
d. 6
(vii) The reaction of toluene with Cl₂ in the presence of FeCl₃ gives predominantly
a. benzoyl chloride
b. benzyl chloride
c. m-chlorotoluene
d. o- and p- chlorotoluene
(viii) Which of the following is most reactive towards nucleophilic addition reactions?
a. CH₃COCH₃
b. CH₃CHO
c. CH₃COC₂H₅
d. HCHO
(ix) Which of the following not affected by temperature?
a. Normality
b. Molality
c. Molarity
d. Formality
(x) Which of these is most acidic?
a. CF₃COOH
b. CCl₃COOH
c. CBr₃COOH
d. CH₃COOH
TRUE / FALSE
(xi) Aldehydes and ketones react with electrophiles but not with nucleophiles.
(xii) The crystal field splitting Δ₀ depends on the field produced by the ligand and charge on the metal ion.
(xiii) Alcohols are more soluble in water than hydrocarbons.
(xiv) Benzaldehyde cannot undergo Cannizzaro reaction.
(xv) [Ni(CN)₄]²⁻ is square planar.
READ THE PASSAGE AND ANSWER THE QUESTIONS (xvi) TO (xx)
Carbohydrates are optically active polyhydroxy aldehydes and ketones or those compounds which on hydrolysis give such compounds are also carbohydrates. The carbohydrates which are not hydrolysed are called monosaccharides. Monosaccharides with aldehydic group are called Aldoses and those with free Ketonic group are called Ketoses. Carbohydrates are optically active. Number of optical isomers = 2ⁿ, where n = number of asymmetric carbons. Carbohydrates are mainly synthesised by plants during photosynthesis. The monosaccharides exist in the form of cyclic structures. In cyclization, the -OH group combines with the aldehydic or ketonic group. As a result, cyclic structures of five or six membered rings containing one oxygen are formed e.g. Glucose, Fructose, Galactose.
(xvi) What are carbohydrates?
(xvii) What are Aldoses?
(xviii) Define Monosaccharides.
(xix) Name a monosaccharide.
(xx) Glucose molecule has four asymmetric carbons. Find the total number of optical isomers in glucose.
SECTION – B
QUESTIONS CARRYING TWO MARKS
Q2. State Henry's law. Write it's two applications.
Q3. Addition of 0.643 g of a compound to 43.95 g of benzene lower the freezing point from 5.51 degree centigrade to 5.03 degree centigrade. If kf for benzene is 5.12 K kg/mol. Calculate the molar mass of the compound.
OR
Calculate mole fraction of water in a mixture of 12 g of water and 92 g ethanol.
Q4. A first order reaction is found to have rate constant, k = 5.5 × 10⁻¹⁴ s⁻¹. Find two-third life period of reaction.
OR
Calculate half life of a first order reaction having K = 4.93 × 10⁻⁴ s⁻¹.
Q5. Write difference between the rate of reaction and rate constant.
Q6. Define the corrosion and give the name of chemical formula of rust.
Q7. Write IUPAC names of following compounds.
K₂[PtF₆]
[CoBr₂(en)₂]Cl
Q8. Write short note on coupling reaction.
OR
Write the uses of ether.
Q9. Write and explain Aldol condensation.
OR
Why are boiling points of carboxylic acids higher than the corresponding alcohols?
Q10. Aniline is less basic than ethylamine, Why?
Q11. What is the chemical name of Vitamin D and which disease is caused by its deficiency?
Q12. How presence of primary amine is confirmed by Carbylamine reaction?
Q13. Write the difference between the double salt and coordination compounds.
Q14. Write general electronic configuration of d-block and f-block elements.
Q15. If a current of 0.5 amp flows through a metallic wire for 2 hours, then how many electrons flow through the wire.
PSEB Guess Papers 2026 – Class 8, 10 & 12 Question Papers |
SECTION – C
QUESTIONS CARRYING THREE MARKS
Q16. A cell reaction is
Ni (s) | Ni²⁺ (0.01 M) // Cu²⁺ (0.01 M) | Cu (s).
Calculate Ecell of a reaction and also write Nernst equation.
Given:
E° (Ni²⁺/Ni) = –0.22 V and
E° (Cu²⁺/Cu) = 0.34 V
OR
The molar conductance of infinite dilution for sodium acetate (CH₃COONa), Hydrochloric acid (HCl) and sodium chloride (NaCl) are 95.5, 426.9 and 120.4 S cm² mol⁻¹ respectively at 298 K. Calculate the molar conductance of Acetic Acid (CH₃COOH) at infinite dilution.
Q17. The rate of chemical reaction doubles for an increase of 10 K in absolute temperature from 298 K. Calculate Ea.
Q18. Discuss the reaction and mechanisms of Acidic Dehydration of ethyl alcohol to prepare ether.
OR
Phenol are more acidic than alcohol. Explain.
Q19. Write the reactions involved in the following:
(i) Hofmann bromamide degradation reaction
(ii) Diazotisation
(iii) Gabriel phthalimide synthesis
SECTION – D
QUESTIONS CARRYING FIVE MARKS
Q20.
(i) Why are Zn, Cd and Hg non-transition elements?
(ii) Which transition metal of 3d series does not show variable oxidation states?
(iii) Why do transition metals and their compounds show catalytic activity?
(iv) Why are melting points of transition metals high?
(v) Why is Cu²⁺ ion coloured while Zn²⁺ ion is colourless in aqueous solution?
OR
(a) Write similarities between Lanthanoids and Actinoids.
(b) Write the difference between the lanthanoids and Actinoid elements.
Q21. Explain the following reactions:
(a) Balz-Schiemann reaction
(b) Finkelstein reaction
(c) Ullmann reaction
(d) Swarts reaction
(e) Gattermann reaction
(1 × 5 = 5)
OR
Why aryl halides are ortho and para directing?
