Will A red blood cell placed in pure water will shrink?

Yes, a red blood cell placed in pure water will shrink. This phenomenon is known as hemolysis.

Red blood cells are specialized cells that contain hemoglobin, an oxygen-carrying protein. They are flexible and can change their shape to pass through narrow blood vessels. However, when they are placed in pure water, the water molecules move into the cell by osmosis, causing the cell to swell and burst.

The reason for this is that the concentration of solutes is higher inside the red blood cell than outside. In order to maintain equilibrium, the water molecules move from the area of lower concentration (outside the cell) to the area of higher concentration (inside the cell). As a result, the red blood cell swells and eventually bursts.

The process of hemolysis can also be observed when red blood cells are placed in a hypotonic solution, which is a solution that has a lower concentration of solutes than the cells. However, red blood cells will not shrink when they are placed in a hypertonic solution, which is a solution that has a higher concentration of solutes than the cells.