Question

the area around a cell has a high concentration of sodium ions. as a result the cell membrane starts to expand and finally bursts. which problem is the cell most likely having

Answer 1

The cell is hypotonic, when the cell over-expands breaks.

Answer 2

The cell will be in a hypotonic condition.  

In this condition, where a cell is placed in a hypo tonic solution, the solvent outside the cell wall starts moving into the cell and the cell will swell. This will continue untill the turgor pressure stops  preventing influx and after this the cell will burst due to increase internal pressure.