Submerging a red blood cell in distilled water (100% water) will result in

The answer is; lysing

This is because the distilled water will be hypotonic in comparison to the cytoplasm of the red blood cell. This means that the distilled water will move, by osmosis, into the RBC. This will cause the cell to engorge and because it has no cell wall (like in plants) the cell membrane will rupture due to the internal water pressure.