Industrial Organic Chemistry-10th Science Notes And Question Bank



Industrial Organic Chemistry

Text Book Question and Answers

I. For each of the following statements or questions four alternatives are given. Choose the most appropriate alternative:

1. The vegetable that contains more sucrose is,

(a)raddish (b)beet root (c)potato (d)green leaves.

Answer :( b) beet root

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

(a)carbon and water vapour. (b)carbon, hydrogen and oxygen.

(c)carbon dioxide and water vapour. (d)carbon dioxide and hydrogen.

Answer:(b)Carbon, hydrogen and oxygen.

3. The residue of sugarcane from which the juice is extracted can be used to prepare,

(a)manure. (b)card board (c)alcohal (d)building material.

Answer:(b)card board

4. During the evaporation of cleaned sugarcane juice, pressure surrounding it, is reduced to,

(a)increase the boiling point (b)maintain the boiling point at 373 K.

(c)decrease the boiling point (d)increase the size of the sugar crystals.

Answer:(c) decrease the boiling point

5. Molecular formula of ethanol is,

(a)CH3OH (b)C2H4(OH)2 (c)C2H5OH (d)HCHO

Answer:(c) C2H5OH

6. The fermented matter of molasses is called,

(a)raw material (b)wort (c)bagasse (d)precipitate


II. Fill in the blanks:

1. Molasses is used to prepare Ethyl alcohol

2. The molecular formula of sucrose is C12H22O11

3. Carbohydrates contain hydrogen and oxygen atoms in the ratio of 2:1

4. The protein matter in the sugarcane juice is coagulated by Steaming

5. The substrate on which Invertase acts is Sucrose to break down

6. Zymase converts Glucose or Fructose into Ethanol

III. Give reason for the following:

1. Coconut shell charcoal is used in the manufacture of sugar.

It is used to decolourise the sugar

2. The shelf life of sucrose is more than that of jaggery

Jaggery is affected by climatic conditions but sugar can be stored easily in any climatic conditions.

3. Evaporation of sugarcane juice syrup is done under reduced pressure.

This is done so that the syrup gets crystallised to give crystals of sugar

4. Saturated sugar solution is sweeter than the solid sugar itself.

The amount of sucrose molecules is more in saturated sugar solution

5. Grape fruits get spoiled easily but not the dry grapes.

Grape fruits having more water content and it promote microbial activities. Therefore grape fruits get spoiled easily but dry grapes do not have any water content.

6. Use of Ethanol as fuel conserves fossil fuels.

Since ethanol is available by using molasses and not petroleum, it conserves fossil fuel.

7. All micro-organisms are not harmful

Some microorganisms are needed by our body to help break down foods in the intestines. These are called good bacteria.


Some micro-organisms help in fermentation of certain materials, hence all micro-organisms are not harmful


IV. Answer the following:

1. Sulphur dioxide gas is also used in some sugar industries to manufacture sugar. What is the property of sulphur dioxide applicable in this case?

Sulphur dioxide is used to remove the colour impurities

2. What is molasses?

During the manufacture of sugar, the uncrystallized syrup is called molasses

3. Briefly explain the steps of manufacturing sugar from sugar cane.

i. Extraction of juice: sugar cane or sugar beet is cut into pieces, crushed in a series of roller mills and juice extracted.

ii. Purification: the juice is warmed and run into settling tanks. It is then decanted, made alkaline with calcium hydroxide. The impurities are precipitated. The liquid is steamed to coagulate protein and allowed to settle.

iii. Concentration and crystallization: the clear juice is concentrated into syrup by evaporation under reduced pressure. The syrup is cooled, to crystallise the sugar. The crystals are dissolved in hot water and decolourised with animal charcoal or coconut shell charcoal and then filtered.

iv. Separation and drying of crystals: the container of sugar cane juice is connected to vacuum pump and heated to evaporate water. The separation of vapour will be at low temperature and sugar can be obtained

4. Why does a piece of cotton cloth get charred when immersed in concentrated sulphuric acid?

Since cotton cloth is made by cellulose it gets charred.

5. In which form do carbohydrates get assimilated in our body?



V. Discuss:

1. There are more friendly bacteria than harmful bacteria.

Many bacteria available are helpful to mankind as they help in many processes like break down foods in the intestines, turning milk into curds. Fermentation of batter of idli and dosa. Fermentation of molasses etc.

2. The ecological balance is maintained by bacteria.

Decomposition of dead and decayed matter is done by bacteria the movement of carbon dioxide, oxygen and water is possible, hence the ecological balance in maintained by bacteria.

3. Our intestines become weak whenever we consume strong antibiotics for the bacteria related diseases.

When strong antibiotics for bacteria related diseases are taken our intestines become weak as the bacteria which helps in digesting food are also destroyed.

4. To make bread, yeast is used but not to make chapathi.

Yeast is used is making bread as it causes fermentation where in the yeast causes chemical decomposition and carbon dioxide is produced raising the dough.


Additional questions and answers

1. What are carbohydrates?

Organic compounds which are made of atoms of carbon, hydrogen and oxygen and occur in foods and living tissues and whose molecules contain hydrogen and oxygen in the ratio 2:1 are called carbohydrates.

2. What is a monosaccharide? Give two examples.

A simple sugar that cannot be hydrolysed to give simpler sugars is called a monosaccharide.

E.g. Glucose, fructose, galactose etc.

3. What is a disaccharide? Give two examples.

A sugar formed by the union of two monosaccharides with the elimination of a molecule of water is called a disaccharide.

E.g. Sucrose, lactose, maltose etc.

4. What are polysaccharides? Give two examples.

A carbohydrate formed by the chemical union of several molecules of simple sugar units is called a polysaccharide.

E.g. Starch, glycogen, cellulose etc.

5. What is sucrose? Write its molecular formula. What is sucrose commonly known as?

A disaccharide formed by the chemical union of glucose and fructose is called sucrose. The molecular formula of sucrose is C12H22O11. Sucrose is commonly called common sugar.

6. Which are main sources of sucrose?

The two main sources of sucrose are sugarcane and beet root.

7. Which are the two simple sugars present in sucrose?

Sucrose is made of two simple sugars namely glucose and fructose.

8. How to form a sucrose

Sucrose is made up of one unit of glucose and one unit of fructose.

C6H12O6 + C6H12O6 ® C12H22O11 + H2O

Glucose + Fructose ® Sucrose + Water

9. State the differences between sugar and jaggery.


Sugar (Sucrose)

1. Jaggery is soft and amorphous.

2. The colour can be among a shade of yellow or brown.

3. Jaggery contains trace minerals along with carbohydrates.

4. Uses natural colouring agents and some mineral ingredients.

5. Jaggery has shorter shelf life.

1. Sugar is solid and crystalline.

2. Sugar is usually bright white in colour.

3. Sugar is simply carbohydrates without micronutrients.

4. Sugar is processed usirtg chemicals.

5. Sugar has longer shelf life.

10. The shelf life of sucrose is more than that of jaggery. Give reason.

Jaggery absorbs moisture and becomes a breeding ground for microbial activity. This is why it gets spoiled easily. Sugar is in the form of dry crystals and does not absorb moisture. Therefore, the shelf life of sucrose is more than that of jaggery

11. What happens when sugar is heated to about 473K? Give the uses of the product.

When sugar is heated to about 473K, it forms a sticky to chew substance called caramel.

Caramel is used for

a. it is used to make hard boiled sugar candy and to coat the chocolates

b. it imparts a characteristic colour and flavour to food.

12. What is a preservative?

A preservative is a chemical that increases the shelf life of food items.

13. What is shelf life?

The duration for which the food items can be preserved is called shelf life.

14. Name the elements are present in carbohydrates

Carbohydrate contains carbon, hydrogen and oxygen.

15. Name the classification of carbohydrates.

Carbohydrates are classified into monosaccharide’s disaccharides and polysaccharides

16. Why does a sugar solution turn soar after a few days?

Sugar solution undergoes fermentation due to the activity of microorganisms. This is why a solution of sugar turns sour after a few days.

17. What are the elements present in sucrose?

The elements that constitute sucrose are carbon, hydrogen and oxygen.

18. What is bagasse?

Bagasse is the cellulose material of the sugarcane residue which is used as a fuel or as raw material to prepare cardboard which is known as celotex.

19. What is celotex?

A type of fibrous cardboard made from cane fibre is called celotex.

20. In the preparation of jaggery, how is the dark colour lightened?

In the preparation of jaggery, the dark colour is lightened by adding a substance called hydrosol.

21. What is hydrosol? What is its use?

Hydrosol is sodium bisulphate which generates sulphur dioxide. It removes colour impurities.

22. What is molasses? What is it used for?

During the manufacture of sugar from cane juice, all sugar does not get crystallized. The uncrystallized sugar syrup which is obtained as a viscous liquid is called molasses. Molasses is used as the starting material in the manufacture of ethyl alcohol.

23. Why is sugarcane juice syrup evaporated under reduced pressure?

Evaporation of cane juice syrup at reduced pressure ensures that the vapourisation is smooth. Reduced pressure lowers the boiling point of the liquid and the vapours separate out at low temperatures. Secondly, evaporation of juice under reduced pressure enables the collection of sugar crystals at lower temperature. ,

24. Why is cooking faster in a pressure cooker?

Pressure cooker cooks food under high pressure conditions, higher pressure increases the boiling point of water. This enables faster cooking.

25. What happens to the boiling point of water at higher altitudes? Why?

The atmospheric pressure decreases with altitude. The boiling point of water thus gets lowered at higher altitudes. This is because the boiling decreases with the decrease in pressure of the surroundings.

26. Suggest two ways to increase the boiling point of water.

The boiling point of water can be increased by (a) increasing the pressure and (b) adding salt to water

27. What are the steps included in fermentation of molasses.

i. Dilution of molasses by water such that the solution contain about 10% sugars.

ii. Addition of yeast and maintaining the temperature range of 308K to 313K.

iii. Distillation of the fermented matter.

28. What is hypoglycaemia and hyperglycaemia?

The condition caused by lowered glucose level in the human blood is called hypoglycaemia. The condition caused by increased blood glucose level in the human body is called hyperglycaemia.

29. Name the hormone that controls the blood sugar level in the human body.

The blood sugar level in the human body is controlled by a hormone called insulin.

30. What is the major constituent of molasses?

The major constituent of molasses is uncrystallized sucrose which appears as viscous syrup.

31. Name the product obtained from molasses.

Ethyl alcohol (ethanol) is obtained from molasses

32. What is the molecular formula of ethyl alcohol? What is its IUPAC name?

The molecular formula of ethyl alcohol is C2H5OH. The IUPAC name of ethyl alcohol is ethanol.

33. What is the process used in the production of ethyl alcohol from molasses?

Ethyl alcohol is produced by the process of fermentation of glucose or fructose.

34. What is meant by fermentation? Give two examples.

The chemical breakdown of an organic substance by bacteria, yeasts, or other microorganisms, typically involving effervescence is called fermentation.

Milk turning into curds, the batter of idli and dosa rising up, the spoilage of cooked wet food are examples of fermentation.

35. What is the name of the microorganism that turns milk into curds?

Bacteria called lacto bacillus changes milk into curds.

36. Milk turns into curds very quickly and becomes sour in summer. Give reason.

Milk is turned into curds by the activity of bacteria called lacto bacillus. These bacteria become active at moderately higher temperature. Therefore, milk turns into curds quickly and becomes sour in summer.

37. What is meant by fermentation of sugar?

The anaerobic conversion of sugar into carbon dioxide and alcohol by yeast is called fermentation of sugar.

38. What is substrate in fermentation?

The matter or the substance that undergoes fermentation is called substrate.

39. What is the microorganism that causes fermentation of sugar?

The fermentation of sugar into alcohol and carbon dioxide is brought about by yeasts.

40. Name the two enzymes involved in the fermentation of molasses.

Fermentation of molasses is brought about by the catalytic action of two enzymes namely invertase and zymase.

41. Dilute sugar solution undergoes fermentation while thick syrup of sugar does not. Give reason


Why is dilution of molasses necessary during the manufacture of ethyl alcohol?

Thick syrup of sugar has high concentration of sugar. This condition is hostile to yeast cells. Yeast cells become active, multiply and produce the required enzymes for fermentation in dilute sugar solution. This is why dilution of molasses is essential.

42. Briefly describe the conversion of molasses into ethyl alcohol.

The molasses obtained during the manufacture of sugar is dissolved in water to get 10% solution. Yeast is added to the solution and the container is closed. The temperature of the solution is maintained around 308 K. Fermentation of sucrose occurs in the container in about a week. The following reactions take place during fermentation:

The fermented matter contains about 6-10% alcohol. The content is subjected to fractional distillation to obtain 95% ethanol.

43. What is the gas commonly produced during fermentation?

Carbon dioxide gas is usually produced during fermentation.

44. How is 95% ethanol obtained from‘wort’?

The fermented molasses (amorphous sucrose) obtained during the production of alcohol is called wort. Wort contains about 6-10% of ethanol. Wort is subjected to fractional distillation to get 95% ethanol.

45. What is the process by which 95% ethanol is obtained from wort?

Wort contains only 6-10% of ethanol. From this, 95% ethanol is obtained by the process of fractional distillation.

46. How does ethanol help to conserve fossil fuels?

Ethanol can be blended with fossil fuels like petrol and diesel. This is possible because ethanol is also a combustible substance. Blending of ethanol into fossil fuels brings down the consumption of fossil fuels and helps to save them

47. What is wort?

Fermented matter is called the wort which contains about 6 to 10 percent of alcohol. It is fractionally distilled to obtain 95% alcohol.

48. Represent the reaction that takes place during fermentation of sucrose.

Alcohol and Ayurveda

In many ayurvedic tonics self generated alcohol is present to a small extent. It stimulates and improves appetite. But methyl alcohol or methanol (CH3OH) is a poisonous substance, even at low concentration.

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