Alcohol measurement — Proof equivalence: 95% (v/v) ethanol corresponds to how many proof degrees (U.S. system)?

Microbiology Industrially Useful Microbial Processes Difficulty: Easy
Choose an option
  • A
    190 proof
  • B
    110 proof
  • C
    170 proof
  • D
    120 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

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