Question

why does the volume of HCl needed to titrate the blank higher than the volume to titrate the sample for when determining saponification value?

Answer 1

sponification value represent the number of miligrams of potassium hdroxide required to sponify 1g of fat under specified conditions. Here the sample is long chain fatty acids in which we are adding sodium hydroxide in order to allow sponification reaction.so already there isacid and base both are present so the volume of hcl required for titration is very low .On the other hand in blank titration no analyte is present hence the volume of hcl we add for blank titration is very much high.