A fuel's refractive index—the ratio of light velocity in air to that in the fuel—provides insight into its_________________?
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Answer: C. Both A. & B.
Explanation
A fuel's refractive index measures how light bends when passing through the liquid hydrocarbon medium. This optical property correlates directly with both the average molecular weight and aromatic content. Higher aromatic concentrations and molecular weights increase the optical refractive index of petroleum fractions. Refractive index is determined experimentally using a refractometer with standardized light wavelengths. Aromatic hydrocarbons possess higher refractive indices compared to paraffinic compounds of similar boiling range. Analytical correlations use refractive index to estimate hydrocarbon type distributions in petroleum cuts.
Refinery laboratories use refractive index measurements for rapid quality control and stream characterization. Knowing aromatic content and molecular weight helps engineers monitor blending operations and product quality. Non-destructive optical testing provides quick insights into complex hydrocarbon mixture properties. The refractive index provides insight into molecular weight, but it also correlates with aromatic content. Limiting the refractive index utility solely to aromatic content ignores its strong correlation with molecular weight. Rejecting both options is incorrect because the refractive index successfully correlates with both properties.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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