Chemistry Flashcards
(28 cards)
What is SAPONIFICATION VALUE
The number of milligrams of potassium hydroxide required to saponify completely one gram of oil or fat
alcoholic The material is saponified by refluxing with a known excess of potassium hydroxide solution. The alkali consumed for saponification is determined by titrating the excess alkali with standard hydrochloric acida using phenolphthalein as indicator
**what is Dean and stark method
The Dean-Stark method is used to measure the moisture content in a sample by extracting moisture with a solvent and distilling it.
How does the Dean-Stark method work?
The method involves heating a mixture of sample and solvent, distilling the vapor, and separating the moisture from the solvent.
What does the determination of volatile oil measure?
It measures the amount of oil that evaporates when the sample is heated.
How is the volatile oil content determined?
By heating the sample and collecting the evaporated oils through distillation or solvent extraction methods.
What does the acid value indicate?
The acid value measures the amount of free fatty acids present in a fat or oil.
How is acid value determined?
By dissolving the sample in a solvent and titrating it with a base using a phenolphthalein indicator.
What does the free fatty acid measurement indicate?
It measures the concentration of free fatty acids in a sample, similar to acid value.
How is the free fatty acid content measured?
By titrating the sample with a standardized base and calculating the percentage of free fatty acids.
What does the peroxide value measure?
The peroxide value indicates the amount of peroxide present, reflecting the extent of oxidation in the sample.
How is peroxide value determined?
By reacting to the sample with a reagent that forms a colored complex with peroxides and measuring the color intensity.
What does the iodine value measure?
The iodine value measures the degree of unsaturation in fats and oils.
How is the iodine value determined?
By reacting to the sample with iodine or a halogen compound and measuring the amount of iodine absorbed.
What is specific gravity?
Specific gravity measures the density of a substance compared to the density of water.
How is specific gravity measured?
By comparing the weight of the sample to the weight of an equal volume of water
What does the saponification value indicate?
The saponification value indicates the amount of alkali required to saponify a fat or oil.
How is the saponification value determined?
By treating the sample with a known excess of alkali and measuring the unreacted alkali.
What does the determination of salt in butter measure?
It measures the amount of salt present in butter.
How is salt content in butter determined?
By titrating chloride ions with silver nitrate or measuring electrical conductivity.
What does the hot air oven method measure?
The hot air oven method measures moisture content in a sample.
How is the moisture content determined using the hot air oven method?
By weighing the sample, heating it in an oven at 105°C until all moisture is evaporated, and then re-weighing to calculate moisture content.
explain Determination of pH value
Determine using pH meter
Liquid symbols can be directly imimmersed
For solid samples in known quantity of sample is allowed to stand for 10 minute in distilled water
What is pH
Measurement of acidity or basicity of a solution
What is unsaponifiable matter
The unsaponifiable matter is that fraction of oil and fat which is not sat. Saponified with caustic alkali and is soluble in nonpolar solvsolvent
The unsaponifiable matter in oil or fat consist of hydrocarbons, higher alcohols, oil, soluble vitamins and sterols
Adulteration of oil and fat with mineral oil or paraffin hydrocarbons will appear in the unsaponifiable matter
