Name the sugar present in sugarcane. What are the hydrolysis products of this sugar? Is this sugar a reducing sugar?
Show Hint
Solution and Explanation
Sugarcane is the primary commercial source of table sugar, a disaccharide.
Step 2: Analysis
The sugar present in sugarcane is
Sucrose ($C_{12}H_{22}O_{11}$). On hydrolysis (acid or enzyme invertase), sucrose yields one molecule of D-glucose and one molecule of D-fructose. Regarding reducing character: sucrose is a non-reducing sugar. The anomeric $C_1$ of glucose and anomeric $C_2$ of fructose are both involved in the glycosidic linkage between the two monosaccharides, leaving no free anomeric $-$OH group available to open the ring and reduce Tollen's or Fehling's reagent.
Step 3: Conclusion
Sucrose cannot act as a reducing agent because it has no free aldehyde or ketone group in equilibrium.
Final Answer: Sugar in sugarcane:
Sucrose. Hydrolysis products: D-Glucose + D-Fructose. It is a
non-reducing sugar.
Top CBSE CLASS XII Chemistry Questions
- ${AgNO_3}$ does not decompose where :
- Azeotropic mixture of water and HCl boils at 381.5 K. By distilling the mixture it is possible to obtain
Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary amines.
(i) (CH3 )2CHNH2 (ii) CH3 (CH2 )2NH2 (iii) CH3NHCH(CH3 )2
(iv) (CH3 )3CNH2 (v) C6H5NHCH3 (vi) (CH3CH2 )2NCH3 (vii) m–BrC6H4NH2
Give one chemical test to distinguish between the following pairs of compounds.
(i) Methylamine and dimethylamine
(ii) Secondary and tertiary amines
(iii) Ethylamine and aniline
(iv) Aniline and benzylamine
(v) Aniline and N-methylanilineAccount for the following:
(i) pKb of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
(iv) Although amino group is o– and p– directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
(v) Aniline does not undergo Friedel-Crafts reaction.
(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines. (vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.
Top CBSE CLASS XII Carbohydrates Questions
Which one of the following is a disaccharide? \[ \text{Glucose, Lactose, Amylose, Fructose} \]
- In the Haworth structure of the following carbohydrate, various carbon atoms have been numbered. The anomeric carbon is numbered as:
- On hydrolysis, which of the following carbohydrates gives only $\mathrm{\beta}$-glucose ?
- On hydrolysis, which of the following carbohydrates gives only glucose ?
- Identify the polysaccharide among the following :
Top CBSE CLASS XII Questions
- 2, b, c are in A.P. and the range of determinant $\begin{vmatrix}1&1&1\\ 2&b&c\\ 4&b^{2}&c^{2}\end{vmatrix}$ is [2, 16]. Then find range of c is
- A boy of mass 50 kg is standing at one end of a, boat of length 9 m and mass 400 kg. He runs to the other, end. The distance through which the centre of mass of the boat boy system moves is
- A capillary tube of radius r is dipped inside a large vessel of water. The mass of water raised above water level is M. If the radius of capillary is doubled, the mass of water inside capillary will be
- A circular disc is rotating about its own axis. An external opposing torque 0.02 Nm is applied on the disc by which it comes rest in 5 seconds. The initial angular momentum of disc is
- A circular disc is rotating about its own axis at uniform angular velocity \(\omega.\) The disc is subjected to uniform angular retardation by which its angular velocity is decreased to \(\frac {\omega}{2}\) during 120 rotations. The number of rotations further made by it before coming to rest is