Final answer:
The gauge pressures inside bubbles are calculated using the formula P = 4T/r, where T is the surface tension and r is the radius. Alcohol forms the most stable bubble due to its surface tension resulting in a bubble pressure that is closest to atmospheric pressure.
Step-by-step explanation:
To calculate the gauge pressures inside bubbles of different liquids, we use the formula for pressure due to surface tension inside a spherical bubble, which is P = 4T/r, where P is the pressure, T is the surface tension of the liquid, and r is the radius of the bubble.
Without the actual values of surface tensions for water, alcohol, and soapy water, we cannot compute the exact pressures. However, we know that alcohol forms the most stable bubble because the absolute pressure inside it is closest to atmospheric pressure. This implies that the surface tension for alcohol is such that it produces a pressure inside the bubble that does not deviate substantially from the outside atmospheric pressure, making the bubble stable.