Benedicts reagent is an indicator for the presence of what in a solution?

1 Answer
Mar 11, 2018

Answer:

Reducing sugar and reducing sugar like substances like creatinine,uric acid,homogentisic acid etc.

Explanation:

Benedict's reagent conatins, #CuS0_4,Na-carbonate and Na-citrate#

In presence of alkaline media created due to #Na-carbonate# reducing sugar undergoes ene-diol transformation as a result of this #Cu^(+2)# in #CuSO_4# (blue) gets reduced to #Cu^+# of #Cu_2O# (red).

#Na-citrate# causes slow release of #Cu^(+2)# from #CuSO_4#

So,change in colour of the solution is indicated as a positive test.

Now,this change in color proceeds through a steps of color changes,which corresponds roughly to certain amount of reducing sugar present.

#Blue - 0%#

#Green -0.5 g %#

#Yellow - 1 g%#

#Oran g e - 1.5 g%#

#Red - 2 g%#

#Brick Red - _-^> 2.5 g %#

So,Benedict's test is also called Semiquantitative test.