Question

An elixir contains 47% v/v alcohol, what is the proof spirit according to USP:

• A. 70%
• B. 82%
• C. 63%
• D. 91%

Answer 1

The Correct Option is B

Step 1: Recall the proof spirit definition.
Proof spirit is fixed so that 57.1% alcohol by volume equals 100 degrees proof, giving a conversion factor of \( \frac{100}{57.1} \approx 1.75 \).

Step 2: Apply the factor to the given elixir.
The elixir contains 47% v/v alcohol, so multiply by the conversion factor:
\[ 47 \times 1.75 \approx 82.3 \]

Step 3: Round to the listed strength.
Rounding 82.3% to the nearest whole percent gives 82%.
\[ \boxed{82\%} \]