Question

What happens when red blood cells are kept in 0.5\% (mass/vol) NaCl solution? Justify your answer.

Hint:

Isotonic solutions are used to maintain the shape of cells, as the osmotic pressure is balanced between the inside and outside of the cell.

Answer 1

When red blood cells are placed in a 0.5\% NaCl solution, they undergo osmosis. Since the concentration of NaCl in the solution is isotonic to that inside the red blood cells, there is no net movement of water into or out of the cells. The cells retain their normal shape and size.