The water will leave the cell as the water concentration in the potato cell would be higher than in the sugar solution, therefore by osmosis water would leave the potato cell and diffuse through a partially permeable membrane into the sugar solution until it is at equilibrium.
Water will leave the cell if the sugar solution has a higher concentration of water because by osmoses, water will diffuse through a partially permeable membrane into the potato cell until it has reached equilibrium.
The potato cell would gain weight if the sugar solution has a higher concentration of water than that of the potato cell, as water molecules will diffuse through a partially permeable membrane until both sides have reached equilibrium this means that the potato cell will gain water molecules, therefore gaining weight. The potato cell would lose weight if the sugar solution had a lower concentration of water than that of the potato cell as water molecules from the potato cell would diffuse through a partially permeable membrane by osmosis, this means that the potato cell would lose water molecules and therefore lose weight.
The weight of the potato would remain the same if the sugar solution and the potato cell has the same concentration of water molecules and were already at an equilibrium, this means that water molecules do not have to diffuse though a partially permeable membrane by osmosis. The concentration of the sugar solution in the potato cell would also be at equilibrium with the concentration of the sugar solution outside.