Microtheme: Biofertilizers/Fuels —
13 questions asked in Prelims in the past.

1. [2025] Consider the following statements:
   Statement I: Of the two major ethanol producers in the world, i.e., Brazil and the United States of America, the former produces more ethanol than the latter.
   Statement II: Unlike in the United States of America, where corn is the principal feedstock for ethanol production, sugarcane is the principal feedstock for ethanol production in Brazil.
   Which one of the following is correct in respect of the above statements?
   • (a) Both Statement I and Statement II are correct and Statement II explains Statement I
   • (b) Both Statement I and Statement II are correct but Statement II does not explain Statement I
   • (c) Statement I is correct but Statement II is not correct
   • (d) Statement I is not correct but Statement II is correct
   Correct Answer: (D) Statement I is not correct but Statement II is correct
2. [2020] According to India’s National Policy on Biofuels, which of the following can be used as
   raw materials for the production of biofuels?
   1. Cassava
   2. Damaged wheat grains
   3. Groundnut seeds
   4. Horse gram
   5. Rotten potatoes
   6. Sugar beet
   Select the correct answer using the code given below:
   • (a) 1, 2, 5 and 6 only
   • (b) 1, 3, 4 and 6 only
   • (c) 2, 3, 4 and 5 only
   • (d) 1, 2, 3, 4, 5 and 6
   Correct Answer: (A) 1, 2, 5 and 6 only
3. [2019] In the context of proposals to the use of hydrogen-enriched CNG (H-CNG) as fuel for buses in public transport, consider the following statements:
   1. The main adyantage of the use of H-CNG is the elimination of carbon monoxide emissions.
   2. H-CNG as fuel reduces carbon dioxide and hydrocarbon emissions.
   3. Hydrogen up to one-fifth by volume can be blended with CNG as fuel for buses.
   4. H-CNG makes the fuel less expensive than CNG.
   Which of the statements given above is / are correct?
   • (a) 1 only
   • (b) 2 and 3 only
   • (c) 4 only
   • (d) 1, 2, 3 and 4
   Correct Answer: (B) 2 and 3 only
4. [2017] It is possible to produce algae based biofuels, but what is/are the likely
   limitation(s) of developing countries in promoting this industry?
   1. Production of algae based biofuels is possible in seas only and not on continents.
   2. Setting up and engineering the algae based biofuel production requires high level of
   expertise/technology until the construction is completed.
   3. Economically viable production necessitates the setting up of large scale facilities which
   may raise ecological and social concerns.
   Select the correct answer using the code given below:
   • (a) 1 and 2 only
   • (b) 2 and 3 only
   • (c) 3 only
   • (d) 1, 2 and 3
   Correct Answer: (B) 2 and 3 only
5. [2015] With reference to ‘fuel cells’ in which hydrogen-rich fuel and oxygen are used to generate
   electriity, consider the following statements :
   (1) If pure hydrogen is used as a fuel, the fuel cell emits heat and water as by-products.
   (2) Fuel cells can be used for powering buildings and not for small devices like laptop
   computers
   (3) Fuel cells produce electricity in the form of Alternating Current (AC).
   Which of the statements given above is/are correct?
   • (a) 1 only
   • (b) 2 and 3 only
   • (c) 1 and 3 only
   • (d) 1, 2 and 3
   Correct Answer: (A) 1 only
6. [2013] With reference to the usefulness of the by-products of sugar industry, which of the following
   statements is/are correct?
   (1). Bagasse can be used as biomass fuel for the generation of energy.
   (2). Molasses can be used as one of the feedstocks for the production of synthetic chemical
   fertilizers.
   (3). Molasses can be used for the production of ethanol. Select the correct answer using the
   codes given below.
   • (a) 1 only
   • (b) 2 and 3 only
   • (c) 1 and 3 only
   • (d) 1, 2, and 3
   Correct Answer: (C) 1 and 3 only
7. [2012] Consider the following kinds of organisms:
   1. Bacteria
   2. Fungi
   3. Flowering plants
   Some species of which of the above kinds of organisms are employed as biopesticides?
   • (a) 1 only
   • (b) 2 and 3 only
   • (c) 1 and 3 only
   • (d) 1, 2 and 3
   Correct Answer: (D) 1, 2 and 3
8. [2012] Biomass gasification is considered to be one of the sustainable solutions to the power crisis in India. In this context which of the following statements is/are correct? 1. Coconut shells, groundnut shells and rice husk can be used in biomass gasification 2. The combustible gases generated from biomass gasification consist of hydrogen and carbon dioxide only 3. The combustible gases generated from biomass gasification can be used for direct heat generation but not in internal combustion engines.
   • (a) 1 only
   • (b) 2 and 3 only
   • (c) 1 and 3 only
   • (d) 1, 2 and 3
   Correct Answer: (A) 1 only
9. [2010] Given below are the names of four energy crops.
   Which one of them can be cultivated for ethanol?
   • (a) Jatropha
   • (b) Maize
   • (c) Pongamia
   • (d) Sunflower
   Correct Answer: (B) Maize
10. [2010] Other than Jatropha curcas, why is Pongamia pinnata also considered a good option for the production of biodiesel in India?
    1. Pongamia pinnata grows naturally in most of the arid regions of India
    2. The seeds of Pongamia pinnata are rich in lipid content of which nearly half is oleic acid
    Which of the statement given above is/are correct?
    • (a) 1 only
    • (b) 2 only
    • (c) Both 1 and 2
    • (d) Neither 1 nor 2
    Correct Answer: (C) Both 1 and 2
11. [2010] Which feature of some species of blue green algae helps promoted them as bio-fertilizers?
    • (a) They convert atmospheric methane into ammonia which the crop plants can absorb readily.
    • (b) They induce the crop plants to produce the enzymes which help convert atmospheric nitrogen to nitrates.
    • (c) They have the mechanism to convert atmospheric nitrogen into a form that the crop plants can absorb readily.
    • (d) They induce the roots of the crop plants to absorb the soil nitrates in larger quantities.
    Correct Answer: (C) They have the mechanism to convert atmospheric nitrogen into a form that the crop plants can absorb readily.
12. [2010] Hydrogen fuel cell vehicles produce one of the following as ‘exhaust’
    • (a) NH3
    • (b) CH4
    • (c) H2O
    • (d) H2O2
    Correct Answer: (C) H2O
13. [2009] In the context of alternative sources of energy, ethanol as a viable bio-fuel can be obtained from:
    • (a) Potato
    • (b) Rice
    • (c) Sugarcane
    • (d) Wheat
    Correct Answer: (C) Sugarcane