Step 1: Respiratory quotient (RQ) is defined as the molar ratio of \( CO_2 \) produced to \( O_2 \) consumed.
Step 2: From the equation:
\( O_2 \) consumed = 12.5 mol
\( CO_2 \) produced = 5.37 mol
Step 3: Therefore,
\[
RQ = \frac{CO_2 \, produced}{O_2 \, consumed} = \frac{5.37}{12.5} = 0.4296 \approx 0.43
\]
\(\therefore\) The respiratory quotient is \(\mathbf{0.43}\).