The difference between the saponification value and the acid value of a lubricant:
the saponification value is measured at room temperature and acid value is measured at high temperature
the acid value is measured by treating with a base at room temperature and saponification value is measured by treating oil with a base at high temperature
C.. the acid value is expressed in numbers and saponification value is expressed as a percentage
D..the acid value measures the acidity of a lubricant while saponification value measures the basicity of a lubricant
Answers
Explanation:
Saponification value number represents the number of milligrams of potassium hydroxide required to saponify 1g of fat under the conditions specified.[1][2][3] It is a measure of the average molecular weight (or chain length) of all the fatty acids present. As most of the mass of a fat/tri-ester is in the 3 fatty acids, the saponification value allows for comparison of the average fatty acid chain length. The long chain fatty acids found in fats have a low saponification value because they have a relatively fewer number of carboxylic functional groups per unit mass of the fat as compared to short chain fatty acids. If more moles of base are required to saponify N grams of fat then there are more moles of the fat and the chain lengths are relatively small, given the following relation:
Number of moles = mass of oil / average molecular mass
The calculated molar mass is not applicable to fats and oils containing high amounts of unsaponifiable material, free fatty acids (>0.1%), or mono- and diacylglycerols (>0.1%).
Handmade soap makers who aim for bar soap use NaOH (sodium hydroxide, lye). Because saponification values are listed in KOH (potassium hydroxide) the value must be converted from potassium to sodium to make bar soap; potassium soaps make a paste, gel or liquid soap. To convert KOH values to NaOH values, divide the KOH values by the ratio of the molecular weights of KOH and NaOH (1.403).
Standard methods for analysis are for example: ASTM D5558 for vegetable and animal fats, ASTM D 94 (for petroleum) and DIN 51559.