Subtopic: Bio-fuels and their use in farm mechanization
Question Statement:
Which of the following statements regarding biodiesel produced via transesterification of vegetable oils (such as Jatropha/Karanja) is/are correct?
Options:
(A) Transesterification converts triglycerides into fatty acid methyl esters (FAME) and glycerol by-product.
(B) Biodiesel has a higher cetane number than petroleum diesel.
(C) Biodiesel possesses higher calorific value (energy density) than petroleum diesel.
(D) Biodiesel contains virtually zero aromatic hydrocarbons and sulfur, reducing particulate matter emissions.
Answer Key:
A, B, D
Step-by-Step Solution & Explanation
• Transesterification reacts vegetable oils with methanol in the presence of an alkaline catalyst, yielding FAME (biodiesel) and glycerol (A is correct).
• Biodiesel generally has a cetane rating between 50–60, higher than standard petrodiesel (~45–50) (B is correct).
• Biodiesel's calorific value (~37–39 MJ/kg) is roughly 10% lower than that of conventional petrodiesel (~42–44 MJ/kg); thus statement C is false.
• Biodiesel is naturally oxygenated and contains negligible sulfur, drastically cutting emissions of unburned HC and PM (D is correct).