Mercury-in-glass thermometers rely on volumetric expansion with temperature rise; which substance experiences the minimum volumetric expansion for a given temperature change?
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Answer: B. Mercury
Explanation
Mercury has a lower volumetric expansion coefficient than typical organic solvents and water. This means mercury expands less in volume per degree of temperature change than methyl alcohol. Despite lower expansion, mercury's wide liquid range makes it ideal for thermometry. Volumetric thermal expansion coefficients quantify fractional volume changes per degree of heating. Organic liquids like alcohol and carbon tetrachloride expand much more aggressively with heat. Water exhibits anomalous expansion behavior near its freezing point, complicating thermometry.
Thermometer design accounts for expansion coefficients to ensure accurate capillary markings. High expansion fluids provide larger scale deflection for small temperature increments. Mercury thermometers require smaller bulbs to achieve readable capillary column movements. Option A water has a higher expansion coefficient than mercury across normal liquid ranges. Option C methyl alcohol exhibits large volumetric expansion compared to heavy liquid mercury. Option D carbon-tetrachloride expands significantly more than mercury for identical temperature rises.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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