Determine the acid value and iodine value of the given oil. Give the principle, procedure and calculations.

1. 1 · Aim. To find the acid value and the iodine value (Wijs) of the given oil (observed during the lab visit).
2. 2 · Principle.
   • Acid value: free fatty acids are titrated with standard KOH using phenolphthalein; mg KOH per g of fat.
   • Iodine value: ICl adds across C=C; unused ICl + KI → I₂, titrated with thiosulphate using starch; g iodine per 100 g of fat.
3. 3 · Requirements.
   • Neutralised alcohol-ether, 0.1 N KOH, phenolphthalein.
   • Chloroform, Wijs solution, 10% KI, 0.1 N thiosulphate, starch.
   • Iodine flasks, burettes, pipettes with a filler, balance, fume hood.
4. 4 · Procedure.
   • Acid value: about 5 g oil + 50 mL solvent + phenolphthalein; titrate with KOH to faint pink.
   • Iodine value: 0.2-0.3 g oil in chloroform + 25 mL Wijs; 30 min in the dark with a blank; add KI and water; titrate with thiosulphate, starch near the end.
5. 5 · Observation. [Table: burette readings for the acid value; blank and sample titres for the iodine value]
6. 6 · Calculation.
   • Acid value = 56.1 × N × V ÷ W, e.g. 56.1 × 0.1 × 0.45 ÷ 5.00 = 0.50 mg KOH/g.
   • Iodine value = (B − S) × N × 12.69 ÷ W, e.g. 20.0 × 0.1 × 12.69 ÷ 0.2700 = 94.0.
7. 7 · Result. Acid value = ___ mg KOH/g; iodine value = ___ g I₂ per 100 g. State what they mean for the oil's quality and unsaturation.
8. 8 · Precautions.
   • Neutralised solvent; first faint pink.
   • Dry flasks, dark, blank; starch near the end.
   • Gloves, goggles, fume hood; no flames; no mouth pipetting.

Scoring tip: Write both definitions word for word and give the basis of 56.1 and 12.69; examiners check these before the arithmetic.