Fehlings Solution No.2 Clear 1L
23608-1L

  dg8 corrosive alkali

Fehlings Solution No.2 500ml

Code 23608

Alternate name:- Fehlings B

CLEAR solution.

contains potasium sodim tartrte [ KNaC4H4O6]

For the determination of invert sugar in conjunction with Fehlings Solution No 1.(Alternate name:- Fehlings A)

U.N Number 1760 ; DG Class 8 ; Packing Group II ( medium risk)

Fehling's test is a chemical analysis used to detect reducing sugars* eg glucsse [ C6H12O6 ] . 

To use:-

Fehlings No.1 [or A])-a  Blue alkaline solution of coppr(II) sulfate

Fehlings No.2 [or B]) - a clear(or water white)solution of  potassium sodium trtrate in sodium hydrxide 

Mix equal parts of No1 (blue) and No2 (clear)

Add to the sample ( use the test solutions in proportion to the sample - so don't overwhelm a small sample with a large amount of test solution ) and heat in a water bath

If there is a brick red precipitate ( Copper(I) oxide) then a reducing sugar is present . No colour change, no reducing sugar..

Principle:  The aldehyde group is oxidized to a carboxylate ion, while the copper(II) tartrte complex is reduced to insoluble copper(I) oxide (red precipitate).

Reducing sugars - these have an aldehyde group - Main  examples -  glucse, fructse, galactose ie all monosaccharides and some disaccharides (lactse, maltose)

Notable exceptions - Sucrose( "sugar")

The net reaction between an aldehyde and the copper(II) ions in Fehling's solution may be written as: RCHO + 2Cu2+ ( copper(II) ions blue in colour) +5OH− ⟶ RCOO−  + Cu2O (Copper(I) oxide red in colour )+3H2O

Where R is the alkyl chain and CHO is the aldehyde "tail" and COO the carboxylate group

Unit Qty: ea

Availability: 4.001 in stock