1

Question 1

conversion of organic N into ammonium by adding sulfuric acid

Answer 1

Digestion

Question 2

conversion of ammonium into ammonia

Answer 2

Distillation

Question 3

titration with sulfuric acid

Answer 3

Titration

Question 4

Form precipitate with dilute HCI

Answer 4

I - Insoluble chlorides

Question 5

• Don’t react with HCI but form precipitate with H2S
• Form precipitates with (NH4)2S

Answer 5

II -
Acid-insoluble sulfides/
Hydrogen sulfide group

Question 6

• Don’t react with all reagents in previous group
• Form precipitates with (NH4)2S

Answer 6

III -
Base-insoluble sulfides/
Ammonium sulfide group

Question 7

• Don’t react with all reagents in previous group
• Form precipitates with either (NH4)2CO3 or (NH4)2HPO4

Answer 7

IV -
Insoluble phosphates/
Insoluble carbonates

Question 8

• Don’t react with all reagents in previous group
• Thus, they stay soluble

Answer 8

V - Soluble group

Question 9

KARL FISCHER REAGENT

• Reacts with water to form sulfur trioxide (SO3)

Answer 9

Sulfur Dioxide

Question 10

KARL FISCHER REAGENT

• Reacts with water to form hydroiodic acid (HI)

Answer 10

Iodine

Question 11

KARL FISCHER REAGENT

• Prevents formation of pyridine-sulfur complex

Answer 11

Anhydrous Methanol

Question 12

KARL FISCHER REAGENT

• Prevents reversal of reaction

Answer 12

Pyridine

Question 13

• difference in weight between total ash and residue after treatment of total ash with water (ignition at 450°C)
• Water soluble Salts
• determine total amount of extractives

Answer 13

Water-Soluble Ash

Question 14

• residue after boiling the total ash with 3N HCl and igniting the remaining insoluble matter (ignition at 450°C)
• silicates/silica portion

Answer 14

Acid-Insoluble Ash

Question 15

Residue left AFTER incineration of an organic material which represents the amount of INORGANIC IMPURITY

Answer 15

ASH CONTENT

Question 16

residue after incinerating at 325 ± 25°C

Answer 16

Total Ash

Question 17

• residue after boiling the total ash with 3N HCl and igniting the remaining insoluble matter (ignition at 450°C)
• silicates/silica portion

Answer 17

Acid-Insoluble Ash

Question 18

• difference in weight between total ash and residue after treatment of total ash with water (ignition at 450°C)
• Water soluble Salts
• determine total amount of extractives

Answer 18

Water-Soluble Ash

Question 19

Hanus Method – Iodobromide TS

Answer 19

USP Method I

Question 20

Wijs Method – Iodochloride TS

Answer 20

USP Method II

Question 21

Hubl Method – HgCl2 + I2

Answer 21

Unofficial Method

Question 22

Iodine value: > 120
Linseed Oil
Cod Liver Oil

Answer 22

Drying Oil

Question 23

Iodine value: 100-120
Cottonseed Oil
Sesame Oil

Answer 23

Semi-drying Oil

Question 24

Iodine value: <100
Olive Oil
Almond Oil

Answer 24

Nondrying oil