Given:
Total solution volume = 361 milliliters
Percentage of acid in the solution = 12.4%
To find the volume of acid:
Volume of acid = (Percentage of acid / 100) * Total solution volume
Volume of acid = (12.4 / 100) * 361
Volume of acid = 0.124 * 361
Volume of acid = 44.764
So, there are approximately 44.76 milliliters of acid in the solution.