When considering the situation described, we have a balloon containing a 10% sugar solution and a beaker containing a 5% sugar solution. The key term here is "osmosis," which refers to the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.
Since the sugar solution inside the balloon has a higher concentration (10%) compared to the solution in the beaker (5%), water will move from the beaker (lower solute concentration) into the balloon (higher solute concentration) in an attempt to equalize the solute concentrations.
Therefore, the correct statement is:
When placed in the beaker, the balloon will gain water by osmosis.