Tag: introduction to carbohydrates

Questions Related to introduction to carbohydrates

The general formula of carbohydrates is:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

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

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

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

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

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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:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  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

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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?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Fructose

  2. Glucose

  3. Starch

  4. Cellulose

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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?

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

Show answer
Correct Option: D