structure. Test the reducing power of a simple aldehyde, formalde- 

 hyde (CHoO) : place a few drops 3% CuSO 4 sol. in a test-tube, 

 add a little formalin, then an equal volume io'/c KOH. Note each 

 stage carefully. Xow heat slowly to the boiling point. Result? 

 Explain. 



14. Repeat the last test with dextrose. Trommer's test: add a 

 few drops 3^ CuSO 4 to the dextrose solution, then half its volume 

 io c /o KOH and boil. Note the result carefully. Trommer's test 

 is in principle like Fehling's test but less delicate. 



15. Boil a little Fehling's solution in a test-tube. Result? Then 

 add some sugar solution and boil again. Result? Fehling's solution 

 is kept in two bottles. Mix equal parts before using. One con- 

 tains CuSO 4 ; the other sodium potassium tartrate ( Rochelle salt) 

 and NaOH. The sodium potassium tartrate is added to hold the 

 Cu(OH) 2 precipitated by the alkali in solution. Fehling's test is 

 very important ; it is used e.g. to detect the presence of sugar in 

 the urine in cases of diabetes. Be sure you understand the reactions 

 underlying the test. 



16. 'Phenyl-hydrazine test. An important means of distinguish- 

 ing different sugars. In a test-tube place a little solid phenyl-hydra- 

 zine hydrochlorate with an equal bulk dry sodium acetate ; then add 

 10 cc. dextrose solution and heat in a water-bath at 100 for one 

 hour. Filter hot. Cool the solution and examine carefully under 

 the microscope. Crystallized compounds, Osazones, are formed, 

 which are characteristic for each sugar. 



III. DISACCHARIDES (QJH,^). 



SUCROSE, LACTOSE, MALTOSE. 



17. Cane-sugar. (Saccharose or sucrose.} Note crystals, taste 

 and solubility as above. Make a i/o solution. Apply Moore's and 

 Fehling's tests. Is it a reducing sugar.' Why not? 



18. Examine lactose (milk-sugar), and maltose (malt sugar), 

 a product of starch hydrolysis, in the same manner as sucrose. 

 Note carefully any differences between these disaccharides. Record 

 the results of your tests with the six sugars in the form of a table. 



19. Inversion of caue-sugar. Boil the solution with a few 

 drops of cone. HC1 for a few minutes. Cool, neutralize, and apply 

 Fehling's test. Result? Explain. What sugars are formed? 



20. Formation of sugar from starcli. Boil dilute starch paste 

 with a little 2O C / H 2 SO 4 till the fluid is clear. Neutralize and test 

 for glucose. Result ? Also test with iodine. Result ? 



1 1 



