Randy Holmes-Farley
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Reef Chemistry Question of the Day # 177
Refractometers can be designed to measure many different chemicals in water, including salt, sugar, and alcohol.
The advertisement linked below, for example, is for a refractometer that measures 0-80% ethanol (alcohol) in water:
http://www.amazon.com/Alcohol-Refractometer-0-80-Water-Grape/dp/B00CP9OVSQ
Based on just the knowledge that it exactly covers the range 0-80% ethanol in fresh water, why would this refractometer not likely be the best for measuring the salinity of seawater?
A. Ethanol lowers the refractive index of freshwater while salt raises it, so it covers an entirely incorrect range.
B. The range of refractive index it covers is too wide, and so it is not precise enough to measure to a reefkeepers requirements.
C. The range of refractive index it covers is too narrow, and so it does not cover the whole range needed for a reef aquarium.
D. Since it is designed for ethanol and not salt, it cannot measure the refractive index of salt solutions correctly
Good luck!
.
Refractometers can be designed to measure many different chemicals in water, including salt, sugar, and alcohol.
The advertisement linked below, for example, is for a refractometer that measures 0-80% ethanol (alcohol) in water:
http://www.amazon.com/Alcohol-Refractometer-0-80-Water-Grape/dp/B00CP9OVSQ
Based on just the knowledge that it exactly covers the range 0-80% ethanol in fresh water, why would this refractometer not likely be the best for measuring the salinity of seawater?
A. Ethanol lowers the refractive index of freshwater while salt raises it, so it covers an entirely incorrect range.
B. The range of refractive index it covers is too wide, and so it is not precise enough to measure to a reefkeepers requirements.
C. The range of refractive index it covers is too narrow, and so it does not cover the whole range needed for a reef aquarium.
D. Since it is designed for ethanol and not salt, it cannot measure the refractive index of salt solutions correctly
Good luck!
.