Ijmb 2026 Chemistry Paper II Organic Question and Answers

*IJMB CHEMISTRY II*

(1)
(a) C₃H₈O₃
(b) C₃H₈O₃
(c) Propane-1,2,3-triol

*NUMBER TWO*

(2a)
Nitration reaction (electrophilic substitution)

(2b)
Reduction reaction (reduces aldehydes, ketones, acids, esters, etc.)

(2c)
Oxidation reaction

(2d)
Friedel-Crafts alkylation (methylation of an aromatic ring)

(2e)
Birch reduction (reduction of aromatic rings)

(3a)
Isotopy is the phenomenon where atoms of the same element have the same atomic number (number of protons) but different mass numbers (different numbers of neutrons).

(3b)
(i) ¹²₆C (Carbon-12)
(ii) ¹³₆C (Carbon-13)
(iii) ¹⁴₆C (Carbon-14)

*QUESTION FOUR*

(4ai)
Stereoisomers are compounds having the same molecular formula and structural formula but differ in the three-dimensional spatial arrangement of atoms or groups within the molecule, thereby giving rise to different properties.

(ii)
They can be distinguished by their optical activity. One stereoisomer rotates plane-polarized light in a clockwise direction while the other rotates it in an anticlockwise direction.

(4b)
When alanine and glycine react, condensation reaction occurs with elimination of water, leading to formation of two dipeptides:

Alanyl-glycine
H₂N–CH(CH₃)–CO–NH–CH₂–COOH

Glycyl-alanine
H₂N–CH₂–CO–NH–CH(CH₃)–COOH