Alcohol measurement — Proof equivalence: 95% (v/v) ethanol corresponds to how many proof degrees (U.S. system)?
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A190 proof
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B110 proof
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C170 proof
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D120 proof
Answer
Correct Answer: 190 proof
Explanation
Introduction / Context:The “proof” scale is frequently used in distillation and ethanol handling. Converting between % alcohol by volume (ABV) and proof is a straightforward calculation yet commonly tested.
Given Data / Assumptions:
- U.S. proof definition: proof = 2 * ABV.
- ABV given: 95%.
Concept / Approach:Apply the linear relation between ABV and proof for the U.S. system. No temperature correction is required for this conceptual question.
Step-by-Step Solution: Let ABV = 95. Compute proof = 2 * 95 = 190. Match to the listed option.
Verification / Alternative check:Everclear 95% ethanol is marketed as 190 proof, confirming the conversion.
Why Other Options Are Wrong:
- 110/120/170 proof: inconsistent with the 2 * ABV rule.
Common Pitfalls:Confusing U.S. proof with historical U.K. proof (different scale) or using % w/w instead of % v/v.
Final Answer:190 proof