The pair of compounds in which both the compounds give positive test with Tollen’s reagent is
Glucose being an aldose responds to Tollen’s test while fructose, although a ketose, undergoes rearrangement in presence of basic medium (provided by Tollen’s reagent) to form glucose, which then responds to Tollen’s test.
The two forms of D-glucopyranose obtained from the solution of D-glucose are called
The two is omeric forms (a – and b –) of D-glucopyronose differ in configuration only at C– 1; hence these are called anomers.
Cellulose upon acetylation with excess acetic anhydride/ H2SO4 (catalytic) gives cellulose triacetate whose structure is
Cellulose is a polysaccharide composed of only Dglucose units. Every adjacent glucose units are joined by β-glycosidic linkage between C1 of one glucose and C4 of the next.
NOTE : Thus in every glucose units only three –OH groups are free to form triacetate.
Among cellulose, poly (vinyl chloride), nylon and natural rubber, the polymer in which the intermolecular force of attraction is weakest is
Nylon and cellulose, both have in termolecular hydrogen bonding, polyvinyl chloride has dipoledipole interaction, while natural rubber has van der Waal forces which are weakest.
The correct statement about the following disaccharide is
The following carbohydrate is
It is a β-pyranose hence it is an aldohexose.
On complete hydrogenation, natural rubber produces
The correct statement(s) about the following sugars X and Y is(are)
We know that carbohydrates having acetal linkage are non-reducing while that with hemiacetal linkage are reducing. In the give structure,
X has acetal linkage, hence non-reducing.
Y has hemiacetal linkage, hence reducing.
Further X is a-anomer, while Y is β-anomer of D-(+)-glucose.
The correct functional group X and the reagent/reaction conditions Y in the following scheme are
Condensation polymers are formed by condensation of a diol or diamine with a dicarboxylic acid.
The structure of D-(+)-glucose is
The structure of L-(–)-glucose is
For ‘invert sugar’, the correct statement(s) is(are)
(Given : specific rotations of (+) -sucrose, (+)-maltose, L-(-)-glucose and L-(+) fructose in aqueous solution are + 66°, +140°, –52° and +92°, respectively)
Invert sugar is an equimolar mixture of D-(+) glucose and D(–) glucose.
• Specific rotation of invert sugar =
• D-glucose on oxidation with Br2-water pr oduces gluconic acid and not saccharic acid.