Organic 2 Review Problem 479

Organic 2 Review Problem 479 - QUANTITATIVE ANALYSIS 463 ....

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
QUANTITATIVE ANALYSIS 463 . , , . . . 25 x 0-00475 x 250 . 250 ml. of the sugar solution contain g. of the cane 23 ' 4 sugar 0 . . 25 x 0-00475 x 250 x IOO A/ .". Sample contains % cane sugar 23*4 X 1-310 = 96*8% cane sugar. NOTE. The use of methylene-blue has been recommended to mark more accurately the complete reduction of Fehling's solution by a reducing sugar. This indicator is prepared by dissolving i g. of powdered methylene-blue in water and diluting to 500 ml. It is used as an internal indicator, a few drops of the methylene-blue solution being added to the Fehling's solution just before reduction is complete. The end-point is indicated by the disappear- ance of the methylene-blue colour, the dye being reduced to a colourless substance immediately an excess of sugar is present. The use of this indicator enables a sharper end-point to be obtained, and its use is specially recommended if the titratlons have to be carried out by artificial light. Estimation
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

Ask a homework question - tutors are online