Practise 53 real Federal Board questions on Fundamental Principles of Organic Chemistry from 2023 to 2026. See the answer and explanation as soon as you answer.
Fundamental Principles of Organic Chemistry is one of the 19 main chapters in our Federal Board FSC Chemistry question bank (11th and 12th class), and about 11% of its real questions come from it. Tayyari Karo has 53 real questions on this chapter from 2023 to 2026; 18 are multiple choice and marked instantly, and the rest are short and long questions with a model answer. By difficulty: 28 medium, 14 easy, 11 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
In a redox reaction, a substance that increases its oxidation number acts as:
Answer: B. Reducing agent
A substance whose oxidation number increases is itself oxidized (loses electrons), so it acts as the reducing agent.
The molecular ion peak gives information about:
Answer: C. Molecular mass of compound
The molecular ion (M⁺) peak in a mass spectrum appears at m/z equal to the molecular mass of the compound.
Empirical formula of an organic compound is C₃H₈O₅ and its molecular mass is 372g/mol. Molecular formula of this compound is:
Answer: C. C₉H₂₄O₁₅
Empirical formula mass = 3(12)+8(1)+5(16) = 124. n = 372/124 = 3, so molecular formula = (C₃H₈O₅)×3 = C₉H₂₄O₁₅.
Heterolytic cleavage of covalent bond converts bonded atoms into:
Answer: B. Both cations and anions
In heterolytic cleavage, both bonding electrons go to one atom, producing one anion (with the electron pair) and one cation (without it).
In UV spectroscopy, which transition requires greater energy?
Answer: A. σ → σ*
σ bonds are the strongest/lowest in energy, so the σ→σ* transition needs the largest energy gap of all these transitions.
Which of the following technique does NOT involve the absorption of radiations?
Answer: B. Mass spectroscopy
Mass spectrometry ionizes and separates molecules/fragments by mass-to-charge ratio; it does not depend on absorption of electromagnetic radiation like NMR, UV/Vis or IR do.
A solute distributes between water and ether at equilibrium, its concentration in ether is 4 g/L and in water is 2 g/L. Find the partition coefficient (Kpc).
Kpc = [conc. in ether (organic)] / [conc. in water (aqueous)] = 4/2 = 2
What is functional Group? Give two examples.
A functional group is a specific atom or group of atoms within a molecule that is responsible for its characteristic chemical reactions/properties, regardless of the rest of the molecular structure. Examples: -OH (hydroxyl, found in alcohols) and -COOH (carboxyl, found in carboxylic acids).
| Session | Questions |
|---|---|
| 2026 Annual | 20 |
| 2025 1st Annual | 9 |
| 2025 2nd Annual | 8 |
| 2024 Annual | 7 |
| 2023 Annual | 9 |
53 real Federal Board (FBISE) Chemistry questions on Fundamental Principles of Organic Chemistry from 2023 to 2026, for 11th and 12th class. Each one shows the session it came from.
No. We could not find an official FBISE marking scheme for these papers, so the answers and explanations are written by Tayyari Karo for practice. Check anything important with your teacher or textbook.
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