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Carbohydrates - definition and classification - class-XII

Description: carbohydrates - definition and classification
Number of Questions: 67
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The general formula of carbohydrates is:

  1. ${C} _{n}{H} _{2n+1}O$

  2. ${C} _{n}{H} _{2n}O$

  3. ${C} _{n}{({H} _{2}O)} _{n}$

  4. ${C} _{n}{({H} _{2}O)} _{2n}$


Correct Option: C
Explanation:
The general formula for any carbohydrate is ${(C{H} _{2}O)} _{n} = {C} _{n}{({H} _{2}O)} _{n}$ 

Invert sugar is:

  1. a type of cane sugar

  2. optically inactive form of sugar

  3. mixture of glucose and galactose

  4. mixture of glucose and fructose in equimolar quantities


Correct Option: D
Explanation:
Sucrose which is an equimolar mixture of glucose and fructose on hydrolysis brings about a change in the sign of rotation from dextro (+) to laevo (-) and the product is named as invert sugar.
Hence, invert sugar is a mixture of glucose and fructose in equimolar quantities.

Which of the following compounds is found in abundance in nature?

  1. Fructose

  2. Glucose

  3. Starch

  4. Cellulose


Correct Option: D
Explanation:

Cellulose is a type of carbohydrate, containing chains of glucose rings. The cell walls, which are responsible for providing support and rigidity to the plants are made of cellulose. 


It is also the primary constituent of wood, making it the most abundant organic compound found in nature.

Hence, the correct answer is option $\text{D}$.

Which of the following carbohydrate(s) can be hydrolyzed?

  1. Fructose

  2. Sucrose

  3. Glucose

  4. Starch

  5. Maltose


Correct Option: A,B,D

Molisch reagent is used to identify following compound?

  1. Glucose

  2. Raffinose

  3. D-oxribose

  4. All of these


Correct Option: D
Explanation:

Carbohydrates undergo dehydration in the presence of sulphuric acid, giving aldehyde as a product which undergoes condensation in the presence of Molisch reagent ($\alpha-napthanol $ dissolved in ethanol) to give a purple colored compound. This forms the basis of Molisch test to detect carbohydrates. Since glucose, raffinose, and deoxyribose are all carbohydrates, they can be identified using Molisch reagent

The reagent which may be used to distinguish between cane sugar and glucose solution is

  1. Molusch's reagent

  2. Iodine solution

  3. Baeyer's reagent

  4. Fehling's solution


Correct Option: D

The two forms of $D-$glycopyranose obtained from solution of $D-$glucose are known as 

  1. Epimers

  2. Anomers

  3. Enantiomers

  4. Geometrical isomers


Correct Option: B

A dextro rotatory sugar present in fruits is

  1. Glucose

  2. Fructose

  3. Cellulose

  4. Starch


Correct Option: A

At a certain temperature when glucose is dissolved in water lowering in vapour pressure is $0.0$ mmHg. What will be the vapour pressure of glucose solution if molality is$1/18$.

  1. $200$mm Hg

  2. $300$ mm Hg

  3. $600$ mm Hg

  4. $720$mm Hg


Correct Option: B

Which of the following sugar is/are exist in furanose form - 

  1. 2-deoxy ribose

  2. a-D-ribose

  3. Fruit sugar

  4. All


Correct Option: D

Which of the following is correct for Lactose

  1. It is nonreducing sugar

  2. Glycosidic bond $[1,4]$ between glucose and galactose

  3. Glycosidic bond $[1,4]$ between glucose and fructose

  4. Glycosidic bond $[1,2]$ between glucose and galactose


Correct Option: B
Explanation:

Lactose $=$ Glycosidic bond $[1,4]$ between glucose and galactose 

Carbohydrates are used by body mainly:

  1. for obtaining vitamins

  2. as a source of energy

  3. for building muscles

  4. for all its development needs


Correct Option: B
Explanation:

Carbohydrates are used by body mainly as a source of energy. 


Carbohydrates represent the most important source of energy for the body, and are vital for a varied and balanced diet. 

The building blocks of all carbohydrates are sugars and they can be classified according to how many sugar units are combined in one molecule. Various forms of sugar, such as glucose and sucrose (table sugar), are simple carbohydrates. 

They are small molecules, so they can be broken down and absorbed by the body quickly and are the quickest source of energy. They quickly increase the level of blood glucose (blood sugar).

Option B is correct.

Which of the following is not a sugar?

  1. Sucrose

  2. Glucose

  3. Fructose

  4. All are sugars


Correct Option: D
Explanation:

Sucrose, glucose and fructose all are sugars. Glucose and fructose are monosaccharides and sucrose is a disaccharide of the two combined with a bond. Glucose and fructose have the same molecular formula $(C _6H _{12}O _6)$ but glucose has a six member ring and fructose has a five member ring structure. Fructose is known as the fruit sugar as its source in the diet is fruits and vegetables. Honey is also a good source. Glucose is known as grape sugar, blood sugar or corn sugar as these are its richest sources. Sucrose is the sugar we know as sugar or table sugar. Typically extracted as cane or beet sugar. If sucrose is treated with acid or heat, it hydrolyses to form glucose and fructose. This mixture of sucrose, glucose and fructose is also called invert sugar.

Which of the following is a source of instant energy?

  1. Salt

  2. Glucose

  3. Water

  4. Starch


Correct Option: B
Explanation:

Glucose is a source of instant energy because it is quick to act to create energy along with oxygen so our body does not need to convert the glucose to anything else. It also can be absorbed through the lining of the stomach.

The products formed when a pinch of sugar is strongly heated for fifteen minutes in a test tube are:

  1. carbon and water vapour

  2. carbon, hydrogen and oxygen

  3. carbon dioxide and water vapour

  4. carbon dioxide and hydrogen


Correct Option: C
Explanation:

Any carbohydrate will give water and $CO _2$ after combustion.

Example: Combustion of Glucose,
$C _6H _{12}O _6 + 6O _2 \xrightarrow{heat} 6CO _2 +6 H _2O$

When sugar is treated with sulphuric acid, we get a very pure form of:

  1. carbon

  2. oxygen

  3. water

  4. hydrogen


Correct Option: A
Explanation:

(A) carbon

Concentrated sulphuric acid is a strong dehydrating agent. Sulphuric acid removes water from organic compounds; it is evident by its charring action on carbohydrates.
${C} _{12}{H} _{22}{O} _{11} \xrightarrow{\text{ conc. } {H} _{2}S{O} _{4}} 12C + 11{H} _{2}O$

Transition state structure of the substate formed during an enzymatic reaction is

  1. Transient but stable

  2. Permanent but unstable

  3. Transient and unstable

  4. Permanent and stable


Correct Option: C
Explanation:

Transition state is intermediate state produced during enzymatic biochemical reaction which is transition state and unstable state

Which enzyme converts glucose to ethanol?

  1. Diesterase

  2. Invertase

  3. Zymase

  4. Both (2) and (3)


Correct Option: C
Explanation:

$Glucose\underrightarrow { Zymase } Ethanal$
Zymase converts glucose to ethanal

The light coming from the sun is stored as energy in plants by the process of photosynthesis. This happens by converting carbon dioxide and water into:

  1. green leaves

  2. carbohydrates

  3. fats

  4. plants hormones


Correct Option: B
Explanation:

Photosynthesis is the process by which plants utilize the energy from the sunlight in order to convert carbon dioxide and water into carbohydrates.

Formula of glucose is :

  1. $C _{5}H _{12}O _{6}$

  2. $C _{6}H _{12}O _{16}$

  3. $C _{6}H _{12}O _{7}$

  4. $C _{6}H _{12}O _{6}$


Correct Option: D
Explanation:

Formula of glucose is $C _6H _{12}O _6$ it is derived from the reaction of photosynthesis that is :


$6CO _2 + 6H _2O \overset{Sunlight}\longrightarrow C _6H _{12}O _6 + 6O _2$

Hence, the correct option is D.

Which of the following compounds will not undergo decomposition on passing electricity through aqueous solution?

  1. Sugar

  2. Sodium chloride

  3. Sodium bromide

  4. Sodium acetate


Correct Option: A
Explanation:

Sodium chloride, sodium bromide, and sodium acetate are all ionic compounds and hence, they dissociate into their respective ions in an aqueous solution. On the contrary, sugar is a covalent compound and hence does not dissociate into ions

The two functional groups present in a typical carbohydrate are :

  1. $-CHO$ and $-COOH$

  2. $-CO$ and $-OH$

  3. $-OH$ and $-CHO$

  4. $-OH$ and $-COOH$


Correct Option: B
Explanation:

Carbohydrates are polyhydroxy aldehydes or polyhydroxy ketones OR compounds which give aldehydic as well as ketonic groups on hydrolysis. Therefore the major functional groups are (carbonyl) Aldehyde, Ketone, and hydroxy groups. 

Out of $1$M glucose and $2$M glucose. 2M glucose has  a higher boiling point.

  1. True

  2. False


Correct Option: A
Explanation:

2 M glucose has a higher boiling point than 1 M of glucose.

Since on increasing the no of moles the molality also increases which is directly proportional to an elevation in boiling point.
Thus, the boiling point of the 2M of glucose will be greater than 1M glucose.

Which among the following is not the example of carbohydrate ?

  1. Glucose 

  2. fractose

  3. Maltose

  4. Nylon


Correct Option: D
Explanation:

$\rightarrow$ Carbohydrates are important source of instant energy in our body system.
$\rightarrow$ Honey has been used as instant source of enrgy in ayurvedic medicines.
$\rightarrow$ Carbohydrates are used as storage starch in plants and glycogen
$\rightarrow$ carbohydrates are also used in textile industry.

So, the correct answer is NYLON (It is a synthetic polymer)

For 'invert sugar', the correct statement(s) is (are)
(Given : specific rotations of (+) -sucrose, (+) -maltose, L-(-)-glucose and L-(+)-fructose in aqueous solution are $+66^0, +140^0, -52^0$ and $92^0$, respectively)

  1. 'invert sugar' is prepared by acid catalyzed hydrolysis of maltose

  2. 'invert sugar' is an eqimolar mixture of D-(+)-glucose and D-(-)-fructose

  3. specific rotation of 'invert sugar' is $-20^0$

  4. on reaction with $Br _2$ water, 'invert sugar' forms saccharic acid as one of the products


Correct Option: A
Explanation:

Invert sugar is a sucrose, partially or totally cleaved into fructose and glucose. Sucrose is converted into  invert sugar by chemical reaction called hydrolysis by heating a mixture or solution of table sugar.

Also, breakdown of sucrose may happen in a reaction catalyzed by enzymes such as sucrose, invertase etc or by acid catalyzed hydrolysis of maltose.

One mole of each of glucose and fructose require $x$ and $y$ moles of periodic acid respectively, for oxidation. Hence, $x/y$ is

  1. $1/1$

  2. $2/1$

  3. $5/4$

  4. $9/4$


Correct Option: A

Molisch test is answered by

  1. All carbohydrates

  2. Sucrose

  3. Fructose
  4. Glucose

Correct Option: A
Explanation:

Molisch test is a test for carbohydrate or compounds which can be dehydrated to furfural or furfural derivatives in the presence of the concentrated sulphuric acid .

In fructose and glucose the possible optical isomers are:

  1. 12, 12

  2. 8, 16

  3. 16, 8

  4. 4, 12


Correct Option: B
Explanation:
Fructose contains three chiral carbon atom and glucose contain 4 chiral carbon atoms.
The Number of possible Optical isomers for Fructose are ${2}^{3} = 8$
The Number of possible Optical isomers for Glucose are ${2}^{4} = 16$
8, 16 is the Answer

The $\alpha$- D glucose and $\beta$- D glucose differ from each other due to difference in carbon atom with respect to its

  1. Number of $OH$ groups

  2. Size of hemiacetal ring

  3. Conformation

  4. Configuration


Correct Option: D

What is the nature of glucose-glucose linkage in starch that males its so susceptible to acid hydrolysis?

  1. Starch is hemiacetal

  2. Starch is acetal

  3. Starch is polymer

  4. Starch contain only few molecules of glucose


Correct Option: B

Rate of reaction depends upon_________?

  1. Temperature

  2. Catalyst

  3. Concentration

  4. All of these


Correct Option: D

Number of $HIO _4$ molecule required to complete oxidation one mole of glucose is :

  1. 4

  2. 5

  3. 6

  4. None of these


Correct Option: A

${ C } _{ 12 }{ H } _{ 22 }{ O } _{ 11 }\longrightarrow 12C+{ 11H } _{ 2 }{ O }$ in presence of concentrated ${ H } _{ 2 }{ SO } _{ 4 }$.

Which of the following is obtained in the above reaction?

  1. Animal charcoal

  2. Sugar charcoal

  3. Coke

  4. Wood charcoal


Correct Option: B

Which of the following does not reduce Benedict's solution?

  1. Sucrose

  2. Aldehyde

  3. Glucose

  4. Fructose


Correct Option: A
Explanation:
 Sucrose.. 
Because Sucrose (table sugar) contains two sugars (fructose and glucose) joined by their glycosidic bond in such a way as to prevent the glucose isomerizing to aldehyde, or the fructose to alpha-hydroxy-ketone form. Sucrose is thus a non-reducing sugar which does not react with Benedict's reagent.

In plant glycolipids, the sugar is normally.

  1. oil

  2. wax

  3. glycolipid

  4. phospholipid


Correct Option: C
Explanation:

Glycolipids yeild fatty acids, glycerol and carbohydrates on hydrolysis. Monogalactosyldiglycerides are glycolipids which are commonly found in plant leaves and algae. They contain a high proportion of poly unsaturated fatty acids and appear to play a role in photosynthesis.

Which of the following is/are correctly matched?

  1. D-Glucose & L-Galactose -Epimer

  2. Fructose & Mannose - Fundamental isomers

  3. D-Glucose & D-Mannose & Diatereomers

  4. $\alpha$-D-Glucopyranose & $\beta-D-Glucopytranose-Anomers


Correct Option: A

Carbohydrates may be:

  1. sugars

  2. starch

  3. polyhydroxy aldehyde/ketones

  4. compounds that can be hydrolyzed to sugar


Correct Option: A,B,C,D
Explanation:

Carbohydrates are primarily produced by plants and form a very large group of naturally occurring organic compounds. Some common examples are cane sugar, glucose, starch, etc.
T
he carbohydrates may be defined as optically active polyhydroxy aldehydes or ketones or the compounds which produce such units on hydrolysis.

Which among the following is the main constituent of Biogas?

  1. Methane

  2. Propane

  3. Butane

  4. Ethane


Correct Option: A

For the reduction of glucose to n-hexane, the reagent used is:

  1. $HBr$

  2. $HCl$

  3. $HF$

  4. $HI$


Correct Option: D
Explanation:

For the reduction of glucose to n-hexane, the reagent used is $HI$.
Glucose is heated with $HI$, n-hexane is obtained which suggests that all the six carbons are linked in a straight chain.

Which of the following is true regarding monosaccharides?

  1. Always have six carbon atoms

  2. Always have five carbon atoms

  3. Always have four carbon atoms

  4. May contain 3 to 7 carbon atoms


Correct Option: D
Explanation:

Monosaccharides may contain 3 to 7 carbon atoms. They have chemical formula $(CH _2O) _{n}$, where conventionally $n=3$. Monosaccharides can be classified by the number of carbon atoms they contain: diose(2), triose(3), tetrose(4), pentose(5), hexose(6), heptose(7) and so on.

Raffinose on hydrolysis forms_________

  1. Glucose

  2. Fructose

  3. Galactose

  4. All of these


Correct Option: D
Explanation:

Raffinose is a trisaccharide and consists of 1 unit of glucose, fructose and galactose each. 


So on hydrolysis, it breaks into glucose, fructose and galactose. 

So, D is correct.

Which of the following is synthetic sweetener?

  1. Saccharin

  2. Aspartame

  3. Dulcin

  4. All of  the above


Correct Option: D
Explanation:

Saccharin, aspartame, dulcin all are synthetic sweetener. They have a sugar-like taste but with less food energy.

Artificial sweeteners are used in one of two ways. They may be used directly in commercially processed foods, or they are mixed with one or more starch-based sweeteners before sale to consumers.


$\therefore$ Option D is the correct answer.

Which of the following is incorrect?

  1. Fructose is reducing sugar

  2. Cellulose has $\beta$-D Glucose units

  3. DNA has D-ribose

  4. Amylopectin is insoluble in water


Correct Option: C
Explanation:

Fructose is reducing sugar.
 
Cellulose is a polysaccharide composed of a linear chain of  $\beta $ 1,4 linked d glucose unit.with a degree of polymerization ranged from several hundreds to over ten thousands.

Amylopectin is a highly branched polymer of glucose found in plants. It is one of the two components of starch, the other being amylose.

As the name suggest DNA is deoxyribonucleic acid hence it has deoxyribose sugar not ribose sugar.

Consider the given statements.
I. Dextrin and glycogen are polysaccharides
II. Lactose and glucose are disaccharides
III.Sucrose and maltose are disaccharides
IV. Raffinose is oligosaccharide
The incorrect statements is/are:

  1. only II

  2. I and II

  3. I, II and III

  4. IV only


Correct Option: A
Explanation:

Option (A) is right. The incorrect statement is (II).
(II) Lactose is a disaccharide while glucose is an aldosic monosaccharide.

Consider the given statements:


I. Maltose is also known as malt sugar.
II. Sucrose is also known as cane sugar.
III. Lactose is also known as grape sugar.
IV. Starch is also known as amylum.

The correct statement(s) is/are:

  1. I, II and IV

  2. I, II and III

  3. II, III and IV

  4. All


Correct Option: A
Explanation:

(I) Maltose is also known as malt sugar.


(II) Sucrose is also known as cane sugar.

(III) Lactose is also known as milk sugar.

(IV) Starch is also known as amylum.

Hence, option A is correct.

Consider the statements about mono, di and oligo saccharides:


I. These are crystalline solids.
II. These are soluble in cold water.
III. These are tasteless.

The incorrect statement(s) is/are:

  1. only III

  2. I, II and III

  3. I and II only

  4. I and III only


Correct Option: A
Explanation:

Monosaccharides, disaccharides and oligo saccharides are crystalline solids, water soluble and sweet in taste. They are called sugar.
Thus only statement III is incorrect.

A carbohydrate which cannot be hydrolysed to simpler compounds is called:

  1. monosaccharide

  2. disaccharide

  3. polysaccharide

  4. oligosaccharide


Correct Option: A
Explanation:

Monosaccharide cannot be hydrolyzed to simpler compounds as it is itself the simplest unit.
Disaccharides, polysaccharides and oligosaccharides can be hydrolyzed to monosaccharides.

Which sugar does not increases the calorific value?

  1. Sucrose

  2. Glucose

  3. Aspartame

  4. Fructose


Correct Option: C
Explanation:

Aspartame is artificial sugar so it does not increases the calorie intake it only induces the sweetness.


Option C is correct.

State whether the following statements are True or False:
Aldohexoses exist in $2^6$ optical forms.

  1. True

  2. False


Correct Option: B
Explanation:

False-Aidohexoses exist in $2^4(= 16)$ optical forms.


Aldohexoses, with four chiral centers, have $2^4$ = 16 stereoisomers.

State whether the following statements are True or False:
Raffinose is a trisaccharide. On hydrolysis, it gives three molecules of glucose.

  1. True

  2. False


Correct Option: B
Explanation:

False-On hydrolysis, it gives three molecules of monosaccharide units one each of glucose, fructose and galactose

State whether the following statements are True or False:
Glucose is more sweeter than fructose

  1. True

  2. False


Correct Option: B
Explanation:

False-Fructose is more sweeter than glucose

To separate a mixture of monosaccharides, you would use :

  1. Centrifuge

  2. Chromatograph

  3. Mass spectrometer

  4. Electrolytic cell

  5. Dialysis


Correct Option: B
Explanation:

Two-dimensional ascending chromatography has been employed to separate a mixture of monosaccharides.

The minimum number of carbon atoms that should be present in a monosaccharide is :

  1. 2

  2. 3

  3. 4

  4. 6


Correct Option: B
Explanation:

Monosaccharide is single polyhydroxy aldehyde (aldose) or ketone (ketose) units. Glucose is a single polyhydroxy aldehyde, while fructose is a single polyhydroxy ketone. A monosaccharide contains a skeleton, of carbon atoms. The minimum number of carbon atoms is three and it can go up to seven.

Carbohydrates that, on attempted hydrolysis, are not cleaved to smaller carbohydrates are called :

  1. oligosaccharides

  2. polysaccharides

  3. disaccharides

  4. monosaccharides


Correct Option: D
Explanation:

A carbohydrate that cannot be hydrolysed further to give simpler unit of polyhydroxy aldehyde or ketone is called a monosaccharide. Some common examples are glucose, fructose, ribose, etc.
Carbohydrates that yield two to ten monosaccharide units, on hydrolysis, are called oligosaccharides. They are further classified as disaccharides, trisaccharides, tetrasaccharides, etc., depending upon the number of monosaccharides, they provide on hydrolysis. Amongst these the most common are disaccharides. The two monosaccharide units obtained on hydrolysis of a disaccharide may be same or different.

Choose the incorrect statement from following:

  1. Monosaccharides are optically active polyhydroxy carbonyl compounds

  2. Fructose does not reduce Fehling's solution becauese it is a ketose

  3. $\alpha$-D(+)-Glucose and $\beta$-D(+)-glucose are anomers

  4. D-Glucose and D-mannose are C-2 epimers


Correct Option: B

Glucose and fructose are both monosaccharides.

  1. True

  2. False


Correct Option: A
Explanation:

Glucose and fructose are both monosaccharides as they cannot be hydrolysed further to simple sugars.

Carbohydrates mix directly with blood and supply energy to the cells.

  1. True

  2. False


Correct Option: B
Explanation:
As we take carbohydrates, our body breaks them simple sugars (glucose, fructose, and galactose) which are absorbed into the bloodstream. Any glucose not needed right away gets stored in the muscles and liver in the form of glycogen.
Therefore, the given statement is wrong

Which enzyme converts glucose to ethanol?

  1. Diesterase

  2. Invertase

  3. Zymase

  4. Both (2) and (3)


Correct Option: C
Explanation:

$Glucose\rightarrow Ethanol$
Zymase enzymes can do above conversion.
(catalyzes fermentation of sugar into ethanol & $CO _2$).

From the following substances, which carbohydrates has the maximum sweetness?

  1. Sucrolose

  2. Saccharin

  3. Aspartme

  4. Alitame


Correct Option: D
Explanation:

All sugars are compared relative to sucrose on the basis of sweetness. Hence, sucrose is rated one in terms of sweetness. 

Alitame is the sweetest among the following with a sweetness rating of 2000, while saccharin, aspartame, and sucralose have a rating of 400, 180, and 600 respectively

Carbohydrates contains carbon, hydrogen, and oxygen molecules.

  1. True

  2. False


Correct Option: A
Explanation:

Carbohydrates are the biomolecules containing carbon, hydrogen, and oxygen respectively. They are also called hydrates of carbon.

Carbohydrates are ___________.

  1. used to make a paper

  2. produced as an intermediate in the synthesis of proteins

  3. the polyhydroxy aldehyde or polyhydroxy ketone

  4. all of these


Correct Option: D
Explanation:

Carbohydrates are polyhydroxy aldehydes or polyhydroxy ketone. Cellulose is a carbohydrate used to make a paper. Carbohydrates are also produced as an intermediate in the synthesis of protein.

Which of the following is not the example of carbohydrate?

  1. Glucose

  2. Maltose

  3. Glycine

  4. Fructose


Correct Option: C
Explanation:

Here Glucose, Maltose, and Fructose are carbohydrate. Glycine is not a carbohydrate. It is a protein.

The polyhydroxy aldehydes are called:

  1. proteins

  2. fats

  3. carbohydrates

  4. vitamins


Correct Option: C
Explanation:
  • Polyhydroxy aldehydes or ketones are molecules with more than one hydroxyl group $(−OH)$, and a carbonyl group $(C=O)$ either at the terminal carbon atom (aldose) or at the second carbon atom (ketose) are called carbohydrates.
  • Monosaccharides are polyhydroxy aldehydes and are called Simple Sugar, any of the basic compounds that serve as the building blocks of carbohydrates. 

D-glucose & D-fructose can be differentiated by :

  1. Fehling solution

  2. Tollens reagent

  3. Benedict test

  4. $Br _2/H _2O$


Correct Option: D
Explanation:

$Br _2/H _2O$ being a mild oxidising agent can only oxidise aldose to carboxylic acids but cannot oxidise ketose.


As glucose contains aldehyde group it gets oxidised and converted into a carboxylic acid and is differentiate from fructose which has ketone group.

Therefore, the correct option is D.

Carbohydrates Contains:

  1. $-CHO$ group

  2. $-OH$ group

  3. $> C=O$ group

  4. All


Correct Option: D

Free aldehyde group can be produced on hydrolysis of which of the following compound(s)?

  1. Maltose

  2. Sucrose

  3. $\alpha$-D Glucose

  4. Lactose


Correct Option: A,B,C,D
Explanation:

 $\alpha$-D glucose has cyclic hemiacetal structure. Hemiacetal on hydrolysis gives free aldehyde group.
Maltose, sucrose and lactose are are disacharides which on hydrolysis gives monosaccharides in which aldehyde group becomes free.
Maltose  $\displaystyle \xrightarrow { \text { hydrolysis} }$ Glucose $\displaystyle + $ glucose.
Sucrose  $\displaystyle \xrightarrow { \text { hydrolysis} }$ Glucose $\displaystyle + $ fructose.
Lactose  $\displaystyle \xrightarrow { \text { hydrolysis} }$ Glucose $\displaystyle + $ galactose.

Which of the following is a physical property of sugar?

  1. It is a white crystalline solid.

  2. Carbon, hydrogen, and oxygen are its constituents.

  3. It turns black when concentrated $\displaystyle { H } _{ 2 }{ SO } _{ 4 } $ reacts with it.

  4. When heated it decomposes.

  5. It decomposes readily.


Correct Option: A
Explanation:

Colour and appearance are physical properties.
The remaining are chemical properties which include its composition, reaction with sulphuric acid and decomposition. 

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