The answer to this question would be hypertonic.
If the chloroplast is going to be pushed against the cell wall, probably the water around the cell wall is decreased, causing it to suck up the water inside. Then, the solution must be causing the cell to lose water. The cell will lose water if put in a hypertonic solution. In a hypertonic solution, the osmotic pressure of the solution is higher than the cell, make it attract water from cells.