Fehlings test Flashcards
(5 cards)
Fehling’s solution is an
alkaline solution containing copper(II) ions which act as the oxidising agent
Fehling’s solution When warmed with an aldehyde, the aldehyde is oxidised to a
carboxylic acid and the Cu2+ ions are reduced to Cu+ ions
In the alkaline conditions, the
the carboxylic acid formed will be neutralised to a carboxylate ion (the -COOH will lose a proton to become -COO- )
The carboxylate ion (-COO-) will form a salt with a positively charged metal ion such as sodium (-COO-Na+)
The clear blue colour of the solution turns
opaque red due to the formation of a copper(I) oxide precipitate
Ketones cannot be oxidised and therefore give a ………….test when warmed with Fehling’s solution
Negative