Skip to content
← Chemistry

Chemistry · Class 12 Science

West Bengal Wbchse Class 12 Chemistry — Real Previous-Year Papers

with complete answers

Real previous-year board papers, year by year — the official exam pattern, the full question paper, and every question solved the concept-first way. Distinct from the chapter-wise textbook bank.

2016–2026
Years of papers
8
Total Papers
8
Real Board Papers
0
Sample papers
260
Real-paper Q & A
0
Sample-paper Q & A

Real board-paper questions available, by year

45 Q20262 sets
35 Q2025complete
35 Q2024complete
35 Q2023complete
40 Q2022complete
—2021Not available
—2020Not available
35 Q2019complete
—2018Not available
—2017Not available
35 Q2016complete

West Bengal HS (WBCHSE) Board 2026 · Set SEM3

Real board examination
Sets

About this paper

The real Class-12 board examination held in 2026. Every question below is solved the concept-first way. Sample papers are labelled honestly — never shown as a past exam.

Total marks
70
Questions
35
Duration
195 min
Sections
5

The marks / questions / duration above are the official exam pattern. We currently have 35 of this paper’s questions (100% of the full paper), with 35 fully solved. Questions we couldn’t yet extract or verify are held — never shown as complete.

Sections & marks

SectionTypeQuestionsMarks eachTotal
1Section 1compulsory14114
2Section 2compulsory414
3Section 3compulsory5210
4Section 4compulsory9327
5Section 5compulsory3515
Total3570

The question paper

The questions we hold for this paper, laid out by section. Solutions are on the Answers tab.

Board Examination

Chemistry

West Bengal HS (WBCHSE) Board 2026 · Set SEM3

Series/Set: SEM3Roll No. ________
Time Allowed: 3 hr 15 minMaximum Marks: 70

General Instructions

  1. This question paper contains 35 questions divided into 5 sections — 1, 2, 3, 4, 5.
  2. Section 1 comprises 14 questions of 1 mark each (compulsory).
  3. Section 2 comprises 4 questions of 1 mark each (compulsory).
  4. Section 3 comprises 5 questions of 2 marks each (compulsory).
  5. Section 4 comprises 9 questions of 3 marks each (compulsory).
  6. Section 5 comprises 3 questions of 5 marks each (compulsory).

Above is the official exam pattern. The questions printed below are those we currently hold for this paper.

Section A

Q1.
Identify X and Y in the following reaction: C6H5-OCH3 (methoxybenzene) + HI -> X + Y
  • (a) X : C6H5-OH, Y : CH3I
  • (b) X : C6H5-I, Y : CH3OH
  • (c) X : C6H5-I, Y : CH3I
  • (d) X : C6H5-OH, Y : CH3OH
[1]
Q2.
Which one of the following polymers is prepared by condensation polymerization?
  • (a) Teflon
  • (b) PAN
  • (c) Nylon-6, 6
  • (d) LDPE
[1]
Q3.
There is a definite sequence of amino acids linked with each other in each polypeptide chain of protein. This sequence of amino acids denotes
  • (a) Primary structure of protein
  • (b) Secondary structure of protein
  • (c) Tertiary structure of protein
  • (d) Quaternary structure of protein
[1]
Q4.
Which of the following bases is absent in DNA?
  • (a) Thymine
  • (b) Guanine
  • (c) Uracil
  • (d) Adenine
[1]
Q5.
At isoelectric point structure of glycine is
  • (a) H2N-CH2-COOH
  • (b) H2N-CH2-COO(-)
  • (c) H3N(+)-CH2-COOH
  • (d) H3N(+)-CH2-COO(-)
[1]
Q6.
Which of the following has zero dipole moment?
  • (a) XeF6
  • (b) XeO3
  • (c) XeF4
  • (d) XeOF2
[1]
Page 1 of 4
Q7.
Which one of the following has lowest electron affinity? (a) Te (b) Se (c) S (d) O
[1]
Q8.
Which one of the following is strongest acid? (a) HOCl (b) HClO2 (c) HClO4 (d) HClO3
[1]
Q9.
Which of the following shows temporary bleaching action through reduction? (a) H2O2 (b) O3 (c) SO2 (d) Cl2
[1]
Q10.
Which of the following statements is not correct about XeF6? (a) Oxidation number of Xe is +6 (b) The hybridization of Xe in XeF6 is sp3d3 (c) The shape of XeF6 molecule is distorted octahedral (d) On hydrolysis XeF6 gives only Xe, HF and O2
[1]
Q11.
Which of the following solutions has the lowest freezing point? (a) 1 (m) sucrose (b) 1 (m) KCl (c) 1 (m) MgCl2 (d) 1 (m) glucose
[1]
Q12.
Which of the following gases does not obey Henry's law? (a) O2 (b) H2 (c) N2 (d) NH3
[1]
Q13.
Lyophobic sol can be protected / stabilised by (a) Boiling (b) Addition of electrolyte (c) Addition of coagulating agent (d) Addition of lyophilic sol
[1]
Q14.
Which one of the following does not involve coagulation? (a) Use of NaCl to stop bleeding (b) Formation of delta (c) Peptization (d) Treatment of pond's water by potash alum
[1]
Q15.
If the elevation in boiling point of a solution of 10 g of non-volatile, non-dissociative, non-associative solute in 100 g of water is dTb and if molar mass of the solute is 100 then Ebullioscopic constant of water 'Kb' is (a) 100 (dTb) (b) dTb (c) dTb / 100 (d) 10 (dTb)
[1]
Q16.
Identify 'P' formed in the following reaction: Br-C6H4-CH2Cl (meta) + CH3ONa / CH3OH -> P (a) Br-C6H4-CH2-OCH3 (ring bears Br and -CH2-OCH3) (b) CH3O-C6H4-CH2-OCH3 (ring bears -OCH3 and -CH2-OCH3) (c) CH3O-C6H4-CH2Cl (ring bears -OCH3 and -CH2Cl) (d) HO-C6H4-CH2OH (ring bears -OH and -CH2OH)
[1]
Page 2 of 4
Q17.
The order of acidic strength for the following compounds is: (I) phenol (C6H5OH), (II) 4-nitrophenol, (III) 4-methylphenol, (IV) 2-nitrophenol (a) II > I > III > IV (b) II > IV > I > III (c) IV > II > I > III (d) IV > II > III > I
[1]
Q18.
The IUPAC name of the following compound is (a chiral carbon bonded to Br, CH3, OH and H) (a) (1R)-1-bromoethan-1-ol (b) (2R)-2-bromoethan-1-ol (c) (1S)-1-bromoethan-1-ol (d) (2S)-2-bromoethan-2-ol
[1]
Q19.
The reagent which can be used for the following transformation is: phenol (C6H5OH) -> salicylaldehyde (2-hydroxybenzaldehyde, OH and CHO on adjacent ring carbons) (a) i) CHCl3, NaOH, 60-80 C ii) dil. HCl (b) i) CO2, NaOH, 120-140 C ii) dil. HCl (c) i) CCl4, NaOH, 60-80 C ii) dil. HCl (d) i) HCHO, NaOH ii) dil. HCl
[1]
Q20.
Which will give yellow precipitate with iodine and alkali? (a) Methanol (b) Propanol (c) Propan-2-ol (d) 2-Methyl-propan-2-ol
[1]
Q21.
Glucose and fructose can be distinguished by which of the following reagents? (a) Tollen's reagent (b) Fehling's reagent (c) Br2 / H2O (d) C6H5-NH-NH2
[1]
Q22.
Hydrolysis of sucrose into glucose and fructose is associated with change in specific optical rotation. The phenomenon is known as (a) Mutarotation (b) Inversion (c) Pyrolysis (d) Racemisation
[1]
Q23.
The catalyst used in addition polymerization of olefins is (a) Ziegler-Natta catalyst (b) Zeolite (c) Wilkinson catalyst (d) Pd-BaSO4
[1]
Q24.
Which of the following polymers contains acrylonitrile as monomer? (a) Orlon (b) Dacron (c) Teflon (d) Nylon
[1]
Q25.
Match Column-I with Column-II and select the correct option: Column-I: (i) P-F Resin, (ii) Neoprene, (iii) Natural rubber, (iv) Nylon-6. Column-II: (a) Chloroprene, (b) Isoprene, (c) Caprolactam, (d) Novolac (a) (i)-(d), (ii)-(a), (iii)-(b), (iv)-(c) (b) (i)-(a), (ii)-(b), (iii)-(c), (iv)-(d) (c) (i)-(b), (ii)-(c), (iii)-(d), (iv)-(a) (d) (i)-(c), (ii)-(d), (iii)-(a), (iv)-(b)
[1]
Q26.
Fog is a colloidal solution of (a) Solid in gas (b) Gas in gas (c) Liquid in gas (d) Gas in liquid
[1]
Page 3 of 4
Q27.
At a given temperature aqueous solution of 0.1 (M) KNO3 is isotonic with aqueous solution of sucrose. What is the concentration of the solution of sucrose? (a) 0.1 (M) (b) 0.3 (M) (c) 0.2 (M) (d) 0.4 (M)
[1]
Q28.
The process of transformation of a freshly prepared precipitate into colloidal solution by adding a suitable electrolyte is called (a) Dialysis (b) Peptization (c) Coagulation (d) Electrophoresis
[1]
Q29.
Which of the following compounds does not contain per-oxo-linkage? (a) H2O2 (b) H2SO5 (c) H2S2O8 (d) H2S2O7
[1]
Q30.
Which of the following pair of compounds acts as both oxidant and reductant? (a) NO, SO3 (b) NO2, H2O2 (c) CO2, SO2 (d) N2O5, O3
[1]
Q31.
An amorphous solid (X) burns in air to form a gas (Y) which turns lime water milky. The gas (Y) decolourises aqueous solution of acidified KMnO4. Gas (Y) reacts with oxygen to give another gas (Z) which is responsible for acid rain. X, Y and Z are (a) X - S ; Y - SO2 ; Z - SO3 (b) X - C ; Y - CO ; Z - CO2 (c) X - P ; Y - PH3 ; Z - P2H4 (d) X - S ; Y - SO3 ; Z - H2SO4
[1]
Q32.
The reaction of toluene with Cl2 in presence of Fe yields the major organic compound (a) benzyl chloride (C6H5-CH2Cl) (b) benzal chloride (C6H5-CHCl2) (c) 4-chlorotoluene (para; ring bears CH3 and Cl at para positions) (d) 3-chlorotoluene (meta; ring bears CH3 and Cl at meta positions)
[1]
Q33.
Which of the following compounds will give racemic mixture on SN1 reaction with aqueous KOH? (I) CH3-CH(C2H5)-Br, (II) CH3-C(CH3)(C2H5)-Br, (III) CH3-CH(CH3)-CH2Br, (IV) CH3-CH2-CH2-CH2-Br (a) I (b) II (c) III (d) IV
[1]
Q34.
Which of the following reactions is not correctly matched? (a) 2CH3Br + 2Na --(dry ether, delta)--> C2H6 + 2NaBr ; Wurtz reaction (b) 2C6H5Br + 2Na --(dry ether, delta)--> C6H5-C6H5 + 2NaBr ; Fittig reaction (c) CH3Br + AgF --(delta)--> CH3F + AgBr ; Schotten-Baumann reaction (d) CH3COOAg + Br2 --(CCl4, delta)--> CH3Br + CO2 + AgBr ; Hunsdiecker reaction
[1]
Q35.
Which one of the following reagents is used in Gattermann reaction? (a) CuCl / HCl (b) Cl2 / Fe (c) HCl / Cu (d) KCl / HCl
[1]
Page 4 of 4