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1. S. niveus
2. S. nodosus
3. S. noursei
4. S. notatus
Ans: 3. S. noursei
Acetyl Value : The acetyl value is the number which expresses in milligrams the amount of potassium hydroxide required to neutralise the acetic acid liberated by the hydrolysis of 1 g of the acetylated substance.
Acetyl value = 1335(b - a)/(1335 – a)
Where, a = saponification value of the substance;
b = saponification value of the acetylated substance.
Acid Value: The acid value is the number which expresses in milligrams the amount of potassium hydroxide necessary to neutralise the free acids present in 1 g of the substance.
Acid value = 5.61 n/w
Where, n = the number of ml of 0.1 M potassium hydroxide required;
w = the weight, in g, of the substance.
Ester Value: The ester value is the number of milligrams of potassium hydroxide required to saponify the esters present in 1 g of the substance.
Ester value = Saponification value – Acid value.
Hydroxyl Value: The hydroxyl value is the number of milligrams of potassium hydroxide required to neutralise the acid combined by acylation in 1 g of the substance.
Iodine Value: The iodine value is the number which expresses in grams the quantity of halogen, calculated as iodine, which is absorbed by 100 g of the substance under the described conditions. It may be determined by any of the following methods.
A : Iodine Monochloride Method or Wijs Method
B : Iodine Monobromide Method or Hanus Method
C : Pyridine Bromide Method
Peroxide Value: The peroxide value is the number of milliequivalents of active oxygen that expresses the amount of peroxide contained in 1000 g of the substance.
Calculate the peroxide value from the expression,
Peroxide value = 10 (a - b)/w
Where, w = weight, in g, of the substance.
Saponification Value: The saponification value is the number of milligrams of potassium hydroxide necessary to neutralise the free acids and to saponify the esters present in 1 g of the substance.
Saponification value = 28.05 (b - a)/w
where, w = weight, in g, of the substance.
Jelly Strength : The jelly strength of Gelatin is the weight, in g, necessary to give a 4 mm depression in a jelly containing 6.67 per cent w/w, matured at 10º, using a plunger 12.7 mm in diameter.
Loss on Drying : Loss on drying is the loss of weight expressed as percentage w/w resulting from water and volatile matter of any kind that can be driven off under specified conditions. The test is carried out on a well-mixed sample of the substance.
Loss on Ignition : Loss on ignition is the loss in weight in per cent w/w resulting from a part of any test material, that is volatilised and driven off under specified conditions. The test is performed on finely powdered material; lumps, if any should be broken up with the aid of a mortar and pestle.