Tag: chemistry

Questions Related to chemistry

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

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Fructose

  2. Sucrose

  3. Glucose

  4. Starch

  5. Maltose

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Correct Option: A,B,D

Molisch reagent is used to identify following compound?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Glucose

  2. Raffinose

  3. D-oxribose

  4. All of these

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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

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Molusch's reagent

  2. Iodine solution

  3. Baeyer's reagent

  4. Fehling's solution

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Correct Option: D

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

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Epimers

  2. Anomers

  3. Enantiomers

  4. Geometrical isomers

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Correct Option: B

A dextro rotatory sugar present in fruits is

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Glucose

  2. Fructose

  3. Cellulose

  4. Starch

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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$1/18$.

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. $200$mm Hg

  2. $300$ mm Hg

  3. $600$ mm Hg

  4. $720$mm Hg

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Correct Option: B

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

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. 2-deoxy ribose

  2. a-D-ribose

  3. Fruit sugar

  4. All

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Correct Option: D

Which of the following is correct for Lactose

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  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

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Correct Option: B
Explanation:

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

Carbohydrates are used by body mainly:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. for obtaining vitamins

  2. as a source of energy

  3. for building muscles

  4. for all its development needs

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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?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Sucrose

  2. Glucose

  3. Fructose

  4. All are sugars

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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.