CSS past paper

CSS Chemistry Paper II Past Paper 2026

CSS Chemistry Paper II 2026 carries 100 marks over 3 hours. It has 7 questions.

Marks: 100
Time: 3 hours
Questions: 7

Years

How to attempt: Attempt ONLY FOUR questions from PART-II. ALL questions carry EQUAL marks.

Questions

Question 1 (Part I) is the paper's MCQs, which are not reproduced here.

Q. 2
- (a)
  How the Resonance Effect plays a significant role to conclude the basic and acidic strengths of molecules. Discuss with relevant examples.
  (12)
- (b)
  How the Hyperconjugation alters the properties of molecules? Discuss.
  (8)
Q. 3
- (a)
  Outline the following reactions of alkenes with suitable examples. (4 each)
  (16)
  - (i)
    Hydrohalogenation
  - (ii)
    Hydration
  - (iii)
    Epoxidation
  - (iv)
    Free-radical Polymerization
- (b)
  Although the halogens are deactivator for electrophillic aromatic substitution but still they are ortho and para directors. Explain.
  (4)
Q. 4
- (a)
  How primary, secondary and tertiary amines can be differentiated by the Hinsberg’s method?
  (9)
- (b)
  Ethanol is the only primary alcohol which gives a positive iodoform test. Outline the mechanism of this reaction.
  (6)
- (c)
  Phenol is converted to salicylaldehyde by the famous Reimer-Tiemann reaction. Draw the mechanism of this reaction.
  (5)
Q. 5
- (a)
  Discuss various classes of compounds which do not have any chiral carbon atoms but still they show chirality.
  (9)
- (b)
  Why 1,2- and 1-3-methylcyclohexanecarboxylic acid are optically active but 1-4-methylcyclohexanecarboxylic acid is not? Elaborate.
  (5)
- (c)
  Allocate the priority to various groups with the help of sequence rules and then assign R or S configuration (whichever is applicable) to the following molecules.
  (6)
  - (i)
  - (ii)
Q. 6
- (a)
  Elucidate a structure that is consistent with each set of $^{1}$ H-NMR data.
  (10)
  - (i)
    $\ce{C11H12O4}$ : δ 10.1 (1H, br s), 7.75 (1H, d, $J$ = 16 Hz), 7.13 (1H, dd, $J$ = 2.1, 8.1 Hz), 7.08 (1H, d, $J$ = 2.1 Hz), 6.89 (1H, d, $J$ = 8.1 Hz), 6.36 (1H, d, $J$ =16 Hz), 3.92 (3H, s) and 3.87 (3H, s).
  - (ii)
    $\ce{C10H10O5}$ : δ 7.71 (1H, d, $J$ = 16 Hz), 6.76 (2H, s), 6.38 (1H, d, $J$ = 16 Hz), and 3. 78 (3H, s).
- (b)
  Sketch out the mass fragmentation pattern in $\ce{CH3CH2COCH2CH2CH3}$ molecule.
  (6)
- (c)
  How can you distinguish between following pairs of compounds with the help of IR spectroscopy? $\ce{PhCONH2}$ and $\ce{PhCH2NH2}$
  (4)
Q. 7
- (a)
  Discuss the chemistry of fatty acids and glyceryl trialkanoates in detail.
  (10)
- (b)
  How the numbering in steroids is carried out? Discuss the reactions and biological functions of cholesterol.
  (10)
Q. 8
- (a)
  Draw a flow-sheet diagram and elaborate the manufacturing and processing of paper in the paper industry.
  (16)
- (b)
  Elaborate why the fertilizers are necessary for proper plant growth.
  (4)

Part-II is to be attempted on the separate Answer Book.
Attempt ONLY FOUR questions from PART-II. ALL questions carry EQUAL marks.
All the parts (if any) of each Question must be attempted at one place instead of at different places.
Write Q. No. in the Answer Book in accordance with Q. No. in the Q.Paper.
No Page/Space be left blank between the answers. All the blank pages of Answer Book must be crossed.
Extra attempt of any question or any part of the question will not be considered.
Use of Calculator is allowed.