Part 4: Microbes in Biogas Production (25 MCQs)
Part 4: Microbes in Biogas Production / Energy Generation (25 MCQs)
Q76. Biogas is mainly composed of:
a) Carbon dioxide only
b) Methane, CO₂, H₂S
c) Nitrogen and oxygen
d) Ammonia and methane
Answer: b
- b) Correct: Biogas = methane (50–70%), CO₂ (30–40%), H₂S (traces).
Q77. Main combustible component of biogas is:
a) CO₂
b) Methane
c) H₂S
d) O₂
Answer: b
- b) Correct: Methane = energy-rich component.
Q78. Biogas is also called:
a) Coal gas
b) Gobar gas
c) Water gas
d) Producer gas
Answer: b
- b) Correct: In India, biogas from cow dung = gobar gas.
Q79. Methane in biogas is produced by:
a) Lactic acid bacteria
b) Methanogenic archaebacteria
c) Yeasts
d) Cyanobacteria
Answer: b
- b) Correct: Methanogens (e.g., Methanobacterium) produce methane.
Q80. In biogas production, microbes act on:
a) Plastic waste
b) Petroleum
c) Cow dung and biomass
d) Metals
Answer: c
- c) Correct: Organic biomass (cow dung, crop residues) → biogas.
Q81. Methanogens belong to domain:
a) Bacteria
b) Archaea
c) Fungi
d) Protista
Answer: b
- b) Correct: Methanogens = Archaebacteria.
Q82. Cow dung is commonly used in biogas plants because:
a) It is free of microbes
b) It contains methanogens naturally
c) It contains high nitrogen content
d) It produces oxygen
Answer: b
- b) Correct: Cow dung already has methanogens (Methanobacterium).
Q83. Biogas plants are most useful in:
a) Cities with industries
b) Rural and dairy-rich areas
c) Seashores only
d) Mountain tops
Answer: b
- b) Correct: Rural areas with livestock → abundant dung for biogas.
Q84. In India, large-scale biogas plants are mainly based on:
a) Human excreta
b) Agricultural waste only
c) Cattle dung
d) Petroleum
Answer: c
- c) Correct: Cattle dung (gobar gas plants).
Q85. The first biogas plant in India was set up at:
a) Pune
b) Khadi and Village Industries Commission (KVIC), Mumbai
c) Delhi
d) Hyderabad
Answer: b
- b) Correct: First plant under KVIC, Mumbai.
Q86. Anaerobic digestion of sludge in sewage treatment also produces:
a) Biogas
b) Pure O₂
c) Steam
d) Nitric oxide
Answer: a
- a) Correct: Biogas generated in sludge digesters.
Q87. Biogas plants help in:
a) Waste management only
b) Energy generation only
c) Fertilizer production only
d) All of the above
Answer: d
- d) Correct: Biogas → energy + sludge manure + waste disposal.
Q88. Biogas is produced in absence of:
a) CO₂
b) Oxygen
c) Water
d) Organic matter
Answer: b
- b) Correct: Anaerobic microbes digest organic waste → methane.
Q89. Which gas gives foul smell in biogas?
a) CO₂
b) H₂S
c) CH₄
d) N₂
Answer: b
- b) Correct: Hydrogen sulphide → rotten egg smell.
Q90. In a biogas digester, slurry is:
a) Unused raw dung
b) Mixture of dung + water (feed material)
c) Biogas only
d) Sterile water
Answer: b
- b) Correct: Slurry = dung + water → fed to digester.
Q91. Effluent left after biogas production is used as:
a) Fertilizer (manure)
b) Fuel directly
c) Antibiotic
d) Insecticide
Answer: a
- a) Correct: Residual slurry = nutrient-rich manure.
Q92. Which of these is NOT a methanogen?
a) Methanobacterium
b) Methanobrevibacter
c) Methanococcus
d) Escherichia
Answer: d
- d) Correct: E. coli is not a methanogen.
Q93. The main purpose of methanogens in biogas plants is:
a) Alcohol fermentation
b) Converting organic acids into methane
c) Fixing nitrogen
d) Producing antibiotics
Answer: b
- b) Correct: Methanogens → convert acetic acid, H₂ + CO₂ → methane.
Q94. Biogas production is an example of:
a) Aerobic respiration
b) Anaerobic digestion
c) Photosynthesis
d) Nitrification
Answer: b
- b) Correct: Anaerobic digestion of organic matter.
Q95. Which Indian state pioneered gobar gas plants?
a) Punjab
b) Gujarat
c) Kerala
d) Odisha
Answer: b
- b) Correct: Gujarat pioneered gobar gas technology.
Q96. In a biogas plant, the dome-shaped structure stores:
a) Slurry
b) Biogas
c) Methanogens
d) Ash
Answer: b
- b) Correct: Gas holder dome → biogas storage.
Q97. Community biogas plants are useful because:
a) They serve many households
b) Reduce pollution
c) Provide fuel + fertilizer
d) All of the above
Answer: d
- d) Correct: Community plants → multiple benefits.
Q98. Biogas is considered eco-friendly because:
a) It increases CO₂
b) It causes global warming
c) It uses renewable waste to produce clean fuel
d) It is a fossil fuel
Answer: c
- c) Correct: Biogas = renewable, eco-friendly energy.
Q99. In a rural biogas plant, what is added daily?
a) Water only
b) Cow dung + water slurry
c) Methanobacterium culture
d) Antibiotics
Answer: b
- b) Correct: Daily slurry input maintains digestion.
Q100. The gas produced in greatest proportion during biogas production is:
a) H₂S
b) CO₂
c) CH₄
d) O₂
Answer: c
- c) Correct: Methane (~70%) = major component.
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