Question

A positive Seliwanoff’s test is obtained with?
A). Glucose
B). fructose
C). Galactose
D). Manonose

Answer 1

Hint: Seliwanoff’s test may be a chemical test which distinguishes between aldose and ketose sugars. If the sugar contains a group , it's a ketose. If a sugar contains an aldehyde radical , it's an aldose. This test relies on the principle that, when heated, ketoses are sooner dehydrated than aldoses.

Complete answer:
Seliwanoff’s test may be a compound test which separates aldose and ketose sugars. This test is far like Bial’s test. This test depends on the rule that, when heated, ketones are more quickly dried out than almonds. It's named after Theodor Seliwanoff, the scientific expert, who performed the test.
Two important things required to perform the experiment are
Seliwanoff’s Reagent.
The material during which you're trying to check the presence of Keto sugar.
To prepare this reagent you'll need HCL, water , and resorcinol. Once you've got these three belongings you are able to prepare the reagent for the test.
First add 34ml of acid in 68 ml of water and then add 0.15 ml of resorcinol. Reagent is prepared to perform the experiment.
A positive Seliwanoff’s test is obtained with Fructose.

So, the correct answer is “Option B”.

Note:
After the test is being performed, you'll observe the colour changes within the solution. If the colour turns to Red, then this suggests that your results are positive and keto sugar is present inside.