1. Which of the following is a characteristic of vegetable oils used in automobile engines?
a) Low viscosity
b) High cetane number
c) Low flash point
d) High sulfur content
Answer: c) Low flash point
Explanation: Vegetable oils typically have a higher flash point compared to conventional petroleum-based fuels. This can lead to challenges in engine combustion and starting, especially in colder temperatures.
2. What process is commonly used to modify vegetable oils for improved performance in engines?
a) Hydrogenation
b) Esterification
c) Polymerization
d) Saponification
Answer: b) Esterification
Explanation: Esterification is a process commonly used to modify vegetable oils into biodiesel, which exhibits improved performance characteristics suitable for use in automobile engines.
3. Which parameter is most crucial for evaluating the performance of vegetable oil-based biodiesel in engines?
a) Octane number
b) Cetane number
c) Vapor pressure
d) Flash point
Answer: b) Cetane number
Explanation: Cetane number is a measure of the ignition quality of diesel fuel. Higher cetane numbers indicate better ignition quality, leading to improved engine performance and reduced emissions.
4. What is a notable advantage of using biodiesel derived from vegetable oils?
a) Increased greenhouse gas emissions
b) Higher sulfur content
c) Lower particulate matter emissions
d) Reduced engine efficiency
Answer: c) Lower particulate matter emissions
Explanation: Biodiesel produced from vegetable oils typically results in lower emissions of particulate matter compared to conventional diesel fuel, contributing to improved air quality.
5. Which alcohol is commonly used as an engine fuel and can be blended with gasoline?
a) Ethanol
b) Methanol
c) Butanol
d) Propanol
Answer: a) Ethanol
Explanation: Ethanol is a commonly used alcohol fuel that can be blended with gasoline to improve octane ratings and reduce emissions.
6. What is a key property of alcohols that makes them suitable for use in automobile engines?
a) High flash point
b) Low viscosity
c) High oxygen content
d) Low energy density
Answer: c) High oxygen content
Explanation: Alcohols contain oxygen in their molecular structure, which promotes more complete combustion and can reduce harmful emissions in automobile engines.
7. Which alcohol is commonly blended with gasoline to produce flex-fuel vehicles?
a) Methanol
b) Ethanol
c) Butanol
d) Propanol
Answer: b) Ethanol
Explanation: Ethanol is commonly blended with gasoline to produce flex-fuel vehicles, allowing them to run on varying proportions of ethanol and gasoline.
8. What is a potential drawback of using methanol-gasoline blends in automobile engines?
a) Reduced engine efficiency
b) Lower octane rating
c) Increased corrosion
d) Higher emissions
Answer: c) Increased corrosion
Explanation: Methanol can be corrosive to certain engine components, which can lead to increased wear and maintenance issues in automobile engines.
9. Which characteristic of alcohols contributes to their ability to improve engine performance when blended with gasoline?
a) Low cetane number
b) High oxygen content
c) Low vapor pressure
d) High sulfur content
Answer: b) High oxygen content
Explanation: The high oxygen content in alcohols facilitates more complete combustion, leading to improved engine performance and reduced emissions when blended with gasoline.
10. What is a notable advantage of using biodiesel compared to alcohol-gasoline blends in automobile engines?
a) Lower energy density
b) Higher greenhouse gas emissions
c) Reduced dependence on fossil fuels
d) Increased particulate matter emissions
Answer: c) Reduced dependence on fossil fuels
Explanation: Biodiesel derived from vegetable oils offers a renewable alternative to conventional diesel fuel, reducing dependence on finite fossil fuel resources and contributing to sustainability efforts.