RBSE Class 12 Biology Chapter 20 – BioEnergy, provides complete information related to the main sources of energy, Biomass, Wood, Biogas, Methane, Bio-diesel, Bio-resources, Petroplants. It also includes detailed explanations of the production of Bio-energy, manufacturing of ethanol from starch and lignocelluloses, gobar gas plant and a lot more.
The important questions are available in RBSE Solutions for Class 12 help students to perform best in their exams. By practising these important questions, students can analyze their preparation.
The Rajasthan Board Class 12 Biology Chapter 20 important questions is the best study material for revisions and last-minute preparations. By practising these important questions, students can gain deep knowledge about the topic and also help them by providing a strategy to prepare for various board examinations and also for medical exams.
RBSE Class 12 Biology Chapter 20 Important Questions
RBSE Biology Chapter 20: MCQ Type Questions
Q.1. The major component of gas is _______________.
(a) CO3 and H2.
(b) CH2 and H2.
(c) CH4 and CO2.
(d) CO2 and SO2.
Sol: (c) CH4 and CO2.
Q.2. Which of the following is an example of fossil fuel?
(a) Alcohol.
(b) Gobar gas.
(c) Petrol.
(d) Hydrogen.
Sol: (c) Petrol
Q.3. Energy obtained from living organisms or biofactor is called _______________.
(a) Bioenergy.
(b) Biofuel.
(c) Biomass.
(d) Mechanical Energy.
Sol:(a) Bioenergy.
Q.4. The presence of __________ gas makes biogas less effective in terms of natural gas.
(a) H2.
(b) CH2.
(c) CO2.
(d) SO2.
Sol: (c) CO2.
Q.5.Which chemical component is added with petrol in automobiles?
(a) Ethanol.
(b) Methanol.
(c) Propanol.
(d) Butanol.
Sol:(a) Ethanol.
Fill in the blanks.
Q.6. _________ source is available in limited quantity in nature.
Sol: Natural resources.
Q.7.Energy obtained from biological factors is called _________.
Sol: Nonrenewable sources of energy
Q.8.The products obtained by the process of photosynthesis are collectively called _______.
Sol: Bio-Energy
Q.9. The ___ is obtained by the process of fermentation of organic compounds by Bacteria.
Sol: Gobar gas
Q.10. Gobar gas contains _________ percent of carbon dioxide.
Sol:31
RBSE Biology Chapter 20: Short Answer Type Questions.
Q.1.Write the names of two petrol plants?
Sol. Euphorbia Lathyris and Hevea brasiliensis.
Q.2. What is petro farming?
Sol. Some plants are used to obtain biodiesel to be used in place of diesel or petrol. These are called petro farming or petro plants. Their cultivation is called a petro crop.
Q.3. What is meant by energy crop?
Sol. Some plants are used as raw materials for the production of ethanol. Example: Sugarcane, sugarbeet, potato, maize, turnip, etc. These plants are called energy plants and their cultivation is called an energy crop.
Q.4. What is the importance of biodiesel?
Sol. The importance of biodiesel are:
- Biodiesel acts as a lubricant, as a result, the efficiency of the engine is increased and the cost of the maintenance is reduced.
- By using this biodiesel, carbon monoxide and suspended particles in the exhaust are comparatively less.
- This is an important source of alternative sources of energy and can lead to employment, increasing income etc.
- Biodiesel may prove effective in economic stability and development in our country as these plants can be grown on barren land, near the roadside and non irrigated lands.
Q.5. What are the benefits of alcohol as a fuel?
Sol. Ethanol can be used in auto vehicles. It can also be used in a pure form or mixed with the petroleum at 5 per cent or 10 per cent or 25 per cent or up to 50 per cent. The use of ethanol as fuel increases the engine energy value and minimises air pollution.
Q.6. Give examples of Petro-plants.
Sol. There are some plant species, which are used in the place of fossil fuels (petrol and diesel). These plants belong to the plant families such as Asclepiadaceae, Apocynaceae, Compositae, Euphorbiaceae, Urticaceae, Sapotaceae, etc. The examples of the Petro-plants are:
- Ficus sp.
- Plumeria sp.
- Calotropis prose.
- Acharyas Zapata.
- Euphorbia Lathyris.
Q.7. What are the salient features of fuelwood?
Sol. Fuelwood should have:
- High-calorie value.
- High combustion efficiency.
- On burning, it produces less smoke and no odour.
- Less water and resin content so that it can be easy to dry.
- It should not break and degrade into small pieces on burning.
Q.8. What are the types of fossil fuels?
Sol. There are three types of fossil fuels, which exist in three different forms.
- Oil is in liquid form.
- Coal is in solid form
- Natural gas is in gaseous form.
Q.9. What is Biomass?
Sol. The chief source of bioenergy is sunlight. Out of total solar energy reaching the earth, only 0.2 per cent is stored in plants in the form of biomass. All the materials formed by photosynthesis form the biomass. As all living organisms depend on the plant for all their needs and also drive energy directly or indirectly from plants, hence all living organisms and their by-products can be induced as biomass.
Read more: Biomass
Q.10. What are the main sources of bioenergy?
Sol. Coal, petroleum, and natural gas are considered the main sources of bioenergy. Other sources include animal fats, vegetable oils, waste cooking oil, biodiesel, biomass, firewood, biodiesel produced from petro plants and vegetable fatty oils, etc.
Q.11. What are the disadvantages of Biomass?
Sol. The main disadvantages of biomass are
- If there’s a demand for biomass then harvesting methods need to be developed.
- If crops are no longer grown then there wouldn’t be any agricultural wastes found.
- The land used for growing crops for biomass is occupied for the long term and which may be in need for other purposes like housing, conservation, farming, resort or agricultural use.
Q.12. What are Non-Renewable Resources?
Sol. Resources which cannot be easily replaced once they are destroyed are called non-renewable resources. Few examples of non-renewable resources include a few species of plants and animals, minerals, fossil fuels, water, wind, land, soil, and rocks.
Q.13. What are Fossil Fuels?
Sol. Fossil fuels are natural resources, obtained as a result of incomplete oxidation, high temperature and pressure for a long time and the subsequent decay of plants, animals and other organic substances wastes inside the earth’s crust. These organic substances play an important role in almost all spectrums of human life. They are also known as non-renewable sources of energy as it takes a very long time for it to replenish.
Q.14. What is Bioenergy?
Sol. Energy obtained from living organisms or biofactor is called Bioenergy. It is one of the many diverse resources available to help meet our demand for energy. It is a form of renewable energy that is derived from recently living organic materials known as biomass.
Q.15. What is Biodiesel?
Sol. The seeds of many plants such as castor, mustard, soybeans, flaxseeds, groundnut, sunflower, jatropha, etc have an adequate amount of lipids and fatty acids. These lipids contain a tremendous amount of energy. During the process of esterification of fatty acids present in these lipids, a liquid is formed which is known as biodiesel.
RBSE Biology Class 12: Long Answer Type Questions
Q.1. Explain in brief about the alternative energy – Biomass and firewood.
Sol. Biomass
Biomass is the main source of alternative energy. The basic source of bioenergy is sunlight. Out of total solar energy reaching the earth, 0.2 per cent of light is stored in plants in the form of biomass. All those materials formed by photosynthesis are called the biomass. We can include all living organisms and their by-products in the category of biomass, which may be a source of energy.
Example of Biomass :
Plants containing lignocellulose are examples of biomass. Lignocellulose is a complex of lignin and cellulose present in the cell walls of woody plants. Plants containing lignocellulose are Maize, Sugarcane, Pine tree, Sugarbeet, Eucalyptus, Leucaena, etc.
Water hyacinth, commonly known as jal-kumbhi is the aquatic flowering plant used in the production of biogas.
Waste products used in the production of biomass are refuse, wood, manure, remains of crops-straw, lemon rinds, remains of sugarcane, fibres of coconut, cow dung, flower- leaf, etc.
Firewood.
Wood is the most commonly used fuel and is being used by humans for a long time. About 40 to 50 per cent of the Indian population use wood fuel for domestic and cottage industries because it is easily available and its use does not require any specific knowledge.
Firewood is used in a maximum amount both in developing and undeveloped countries of Asia and Africa. The use of wood as a fuel in our country is a major cause of deforestation and destruction of wildlife and also a major source of environmental pollution in our country.
Salient features of good wood fuel are:
- It must have a high combustion potential.
- It should not split and break into pieces on combustion.
- The amount of moisture and resins content should be low.
- It must have high-calorie value so as to generate more heat on combustion.
- It should not produce stinking odour on combustion and should produce minimum smoke.
Q.2. Explain the process of the formation of gobar gas.
Sol. More than 70 per cent of the population of our country resides in villages, where animal livestock is plentiful and easily available. Generally, the dung obtained from the castles is used for burning by making cow-dung cakes. Instead of burning, the dung should be utilized for making biofertilizers. For this, the dung should be filled into big pits regularly. The pit should be made on a higher level and its depth should not exceed on the metre.
Fermentation of organic compounds is done by the bacteria and the produced is known as biogas. In India, cow dung is used for biogas production. This is a cheap source of energy and also plays an important role in controlling environmental pollution.
The gobar gas is also called biogas.
In Gobar gas plant, the anaerobic fermentation is completed in three steps:
First Phase
Aerobic bacteria convert complex organic compounds such as cellulose and hemicellulose into simple compounds.
Second Phase
Both aerobic and anaerobic bacteria convert the simplest components into carbonic acid and finally acetic acid.
Third Phase
In the third phase, the Methanobacteria converts acetic acid into methane gas. The residue of the biogas plant is called slurry and the dried slurry is later used as manures.
The capacity of the gobar gas is little less than the natural gas. The first gobar gas research station was established at Ajitmal in the Etawah district of Uttar Pradesh state in India.
A Gobar Gas Plant
Q.3. What are the advantages and disadvantages of Biogas?
Sol. Advantages of Biogas
- It is considered as a renewable source of energy.
- It is a non-polluting gas, which limits the cause of air pollution.
- Biogas plants require very little installation cost and become self-sufficient in a span of 3-4 months.
- The slurry produced after the production of biogas is used as manure in fields. The method of disposal is safe and efficient and hence no space is wasted in the form of landfills.
Disadvantages of Biogas
- It is difficult to enhance the efficiency of biogas.
- It is not economically viable to use biogas on a large scale.
- It contains many impurities which are difficult to be controlled even after rounds of purification.
- When methane comes in contact with oxygen it reacts violently to produce carbon dioxide. The highly inflammable nature of methane makes it prone to explosions.
Know more : Biogas
Q.4. Explain in brief about the alternative energy Biogas and Biodiesel.
Sol. Biogas
Biogas is a renewable energy source produced by the breakdown of organic matter by certain bacteria under anaerobic conditions. It is a mixture of methane, hydrogen, and carbon dioxide. It can be produced by agricultural waste, food waste, animal dung, manure, and sewage. The process of biogas production is also known as anaerobic digestion.
Biogas recycles the waste products naturally and converts them into useful energy, thereby, preventing any pollution caused by the waste in the landfills, and cutting down the effect of the toxic chemicals released from the sewage treatment plants.
Biogas converts the harmful methane gas produced during decomposition, into less harmful carbon dioxide gas. The biogas production is carried out in anaerobic digesters known as Biogas plants. It is also known as a gobar gas.
Biodiesel
Biodiesel is a renewable, biodegradable fuel that is manufactured from vegetable oils, and animal fats. Biodiesel is a renewable, alternative clean-burning fuel similar to conventional diesel. It is produced using animal fats, vegetable oils and waste cooking oil. Due to its biodegradable nature, it is used as a substituent for fossil diesel fuel. It can also be mixed with petroleum diesel fuel in any proportion. The seeds of many plants such as castor, mustard, soybeans, flaxseeds, groundnut, sunflower, jatropha, etc have an adequate amount of lipids and fatty acids. These lipids contain a tremendous amount of energy. During the process of esterification of fatty acids present in these lipids, a liquid is formed which is known as biodiesel.
Q.5. What is Renewable Energy? Give examples of Renewable Energy
Sol. Renewable energy can be defined as energy, which is produced from natural processes and continuously replenished. The energy that is provided by renewable energy resources is used in different important areas such as air and water cooling/heating, electricity generation, the rural sector and transportation. It can never be depleted. The importance of renewable energy is invaluable.
Examples of Renewable Energy
These types of energy sources are different from fossil fuels, such as oil, coal, and natural gas. Some examples of renewable energy sources are:
- Wind energy.
- Solar energy.
- Hydropower.
- Biomass energy.
- Geothermal energy.
Q.6. Explain the process of obtaining alcohol from starch and cellulose.
Sol.
Starch crops – rice and millets and sugar plants – sugarcane and beetroot are the important crops for biofuel production. Starch and sugars obtained from these plants can be converted into ethanol. Cellulose is an important product of plants and with the help of cellulose enzymes, it can be broken down into glucose and finally into ethanol.
In woody plants lignin is also found along with the cellulose as lignocellulose. With the help of enzymes, lignocellulose can be converted into sugar and with the help of yeast cells, this sugar is converted into ethanol by the process of fermentation. Some plants such as sugarcane, potato, beetroot are used as raw materials for ethanol production. These plants through which ethanol is produced are called energy plants. New techniques are being developed to use this ethanol in automotive.
Brazil is the leading country to use this technique. In Brazil, the Brazilian National Alcohol Program was started in 1975.
Now in Brazil, all cars are running on alcohol or 20 per cent mixture of ethanol with petrol.
Sugarcane is one of the main cash crops grown in many states in India. Molasses are bi-product of the sugar industries.
65.5 percent of pure ethanol is produced from molasses but for mixing with petrol, 66.8 percent ethanol purity is required. BY using distillation plants, 66.8 percent ethanol can be derived from molasses by modification.
In India, there are three plants, which are established for mixing 5 per cent ethanol with petrol for experiment purposes. Among these three plants one is situated in Bareilly in Uttar Pradesh state, and other two in Manmard and Meeraj in Maharashtra state.
Q.7. Explain in brief about the alternative energy – Biomass and firewood.
Sol.
Biomass.
The chief source of bioenergy is sunlight. Out of total solar energy reaching the earth, only 0.2 per cent is stored in plants in the form of biomass. All the materials formed by photosynthesis form biomass. As all living organisms depend on the plant for all their needs and also drive energy directly or indirectly from plants, hence all living organisms and their by-products can be induced as biomass. Plants containing lignocellulose are examples of biomass.
Firewood.
Wood is the most commonly used fuel and is being used by humans for a long time. About 40 to 50 per cent of the Indian population use wood fuel for domestic and cottage industries because it is easily available and its use does not require any specific knowledge.
Firewood is used in a maximum amount both in developing and undeveloped countries of Asia and Africa. The use of wood as a fuel in our country is a major cause of deforestation and destruction of wildlife and also a major source of environmental pollution in our country.
Q.8. What is an Algae hydrogen factory?
Sol. Algae Hydrogen Factory
Algae are the photosynthetic aquatic plants and under normal conditions, they produce carbohydrates and oxygen by the process of photosynthesis as of higher plants.
In the year 2000, Anastasios Melis proved in his experiments that during the day time, if the supply of oxygen and sulphur is stopped to algae then the metabolic reactions in algae changes and they start producing hydrogen in place of oxygen in photosynthesis.
We know that hydrogen is highly inflammable gas, so can be an important source of energy. If these experiments will be successful, this would become a great source of energy in future.
Q.9. Difference Between Renewable and Nonrenewable Sources of Energy
Sol.
| Renewable Sources of Energy | Nonrenewable Sources of Energy |
| The resources can be renewed or replaced | The resources that cannot be renewed once they are consumed |
| Do not cause any pollution to the environment. | Cause pollution to the environment. |
| Renewable resources are inexhaustible. | Non- Renewable resources are exhaustible. |
| Renewable resources are not affected by human activities. | Non- Renewable resources are affected by human activities. |
| Examples of Renewable resources- Air, water and solar energy | Examples of Renewable resources- Mineral, oil, and Coal |
Q.10. What is Biodiesel? State the important features of Biodiesel.
Sol. Biodiesel is a renewable, biodegradable fuel that is manufactured from vegetable oils, and animal fats. Biodiesel is an alternative clean-burning fuel similar to conventional diesel. It is produced using animal fats, vegetable oils, and waste cooking oil. Due to its biodegradable nature, it is used as a replacement for fossil diesel fuel. It can also be mixed with petroleum diesel fuel in any proportion. The seeds of many plants such as castor, mustard, soybeans, flaxseeds, groundnut, sunflower, jatropha, etc have an adequate amount of lipids and fatty acids. These lipids contain a tremendous amount of energy. During the process of esterification of fatty acids present in these lipids, a liquid is formed which is known as biodiesel.
The important features of biodiesel are:
- Biodegradable and Renewable Fuel.
- Lower exhaust emission rate than normal diesel fuel.
- Safer to use and has low toxicity compared to fossil diesel fuel.
- Using biodiesel doesn’t require any diesel engine modification.
- As per ASTM D 6751 quality parameters, the quality of diesel is analyzed.
Q.11. Name the plants which provide good quality fuelwood.
Sol. There are many plants which are used against the fossil fuels These plants are called the good quality of fuelwood. Plants which provide good quality of fuelwood are as follows:
| Common Name | Botanical Name |
| Desi babool | Acacia Nilotic |
| Kumba | Acacia Senegal |
| Angrezi babool | Prosopis Juliflora. |
| Khair | Acacia catechu |
| Siris | Albizia lebbeck |
| Jamun | Syzygium cumin |
| Khejri | Prosopis cineraria |
| Maha neem | Azadirachta indica A. |
| Mango | Mangifera indica |
| Indian olibanum | Boswellia cirrela |
| Dhokla | Anogeissus pendula |
| Houzz | Acacia leuco Florida |
Q.12. Explain the process of the production of Biodiesel.
Sol.
Production of Biodiesel
India is able to produce only 30 percent of petroleum products of its requirements and rest of the 70 percent of petroleum products are imported.
At present 5 to 6 percent of biodiesel is mixed with petroleum diesel inorder to save a lot of foreign currency.
According to the research, the oil obtained from Jatropha curcas can be used as biodiesel. The planning commission has planned to grow the trees of Jatropha and Pongamia pinnata as a source of biodiesel.
This will be important for the ecology and conservation of biodiversity. This will become a source of employment and will generate income for financially backwards people and farmers.
Cultivation of Jatropha is not only important from the viewpoint of biodiesel production but through this, the uncultivated land can also be brought under cultivation.
Importance of Biodiesel.
- Biodiesel also acts as a lubricant. It increases the efficiency of the engine and the cost of maintenance is reduced.
- By using the biodiesel, carbon monoxide and suspended particle emission is comparatively less.
- This is an alternative source of energy and can lead to generating employment and increasing income, etc.
- Biodiesel is one of the best alternative sources of fuel. This can be obtained by growing Petro plants in less productive and barren lands.
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