Tag: chemistry

Questions Related to chemistry

Which among the following is not the example of carbohydrate ?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Glucose 

  2. fractose

  3. Maltose

  4. Nylon

Show answer
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)

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  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

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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

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. $1/1$

  2. $2/1$

  3. $5/4$

  4. $9/4$

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Correct Option: A

Molisch test is answered by

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. All carbohydrates

  2. Sucrose

  3. Fructose
  4. Glucose
Show answer
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:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. 12, 12

  2. 8, 16

  3. 16, 8

  4. 4, 12

Show answer
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

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Number of $OH$ groups

  2. Size of hemiacetal ring

  3. Conformation

  4. Configuration

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Correct Option: D

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

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Starch is hemiacetal

  2. Starch is acetal

  3. Starch is polymer

  4. Starch contain only few molecules of glucose

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Correct Option: B

Rate of reaction depends upon_________?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Temperature

  2. Catalyst

  3. Concentration

  4. All of these

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Correct Option: D

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

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. 4

  2. 5

  3. 6

  4. None of these

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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?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Animal charcoal

  2. Sugar charcoal

  3. Coke

  4. Wood charcoal

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Correct Option: B