Red blood cells have a solute concentration of around 0.9%  when these cells are immersed in a 1% salt solution they will shrink.

• As 1% salt solution is hypertonic as compared to the cell and whenever any cell is placed in hypertonic solution water moves from the cell to the outside by osmosis and resulting in shrinking.
• As we know water moves from an area of high osmotic pressure to low osmotic pressure, in this case, the cell has higher osmotic pressure compared to the salt solution.
• And whenever a cell is placed in hypotonic solution it will swell and may burst, as in this case water will move from the outside to the inside of the cell.
• And whenever a cell is placed in an isotonic solution nothing will occur. water will neither flow out nor in.