CARBOHYDRATES 223 



ii. Try F elding 's Test. Saccharose does not reduce Fehling's 

 solution on short boiling since it has no free aldehyde or ketone 

 group. Try boiling for several minutes. On prolonged boiling 

 some reduction takes place. 



iii. Barfoed's Test. If saccharose does not reduce Barfoed's 

 solution on boiling for a short time, try the effect of prolonged 

 boiling. Note the length of time required for any reaction to 

 take place, and compare it with the time in which dextrose 

 brought about a reduction. 



iv. Nylander's Test. 



v. PJienylliydrazine. Cane sugar forms no osazone*. 



vi. Inversion of Saccharose. By boiling with dilute acids sac- 

 charose may be broken up into dextrose and levulose. After 

 ascertaining that the saccharose solution will not reduce Fen- 

 ling 's, take another sample of saccharose solution, acidify slightly 

 by adding about 1 c.c. of dilute sulphuric acid and heat on the 

 water bath for 15 minutes. Test again with Fehling's solution. 

 The saccharose will have been hydrolyzed into dextrose and 

 levulose, and the liquid should reduce Fehling's solution. 



vii. Optical Activity Before and After Inversion. Determine 

 the rotation of the solution of saccharose. Determine the rota- 

 tion of a portion of the same solution which has been inverted. 

 The rotation should now be to the left, since the solution contains 

 equal amounts of dextrose and levulose, and the latter is stronger 

 levorotatory than the former is dextrorotatory. 



viii. Perform a Fermentation Test with Saccharose. It fer- 

 ments readily. 



b. Maltose. Repeat the following tests performed on sac- 

 charose, using a maltose solution: 



i. Solubility in water, alcolwl and ether. 

 ii. Feliling's. 

 iii. Barfoed's. 

 iv. Nylander's. 

 v. PJienylhydrazine. 

 vi. Fermentation. 



