Why isosmotic NaCl glucose urea and ammonium chloride produced different osmotic phenomena on RBC?

These substances have different molecular sizes and charges, which can affect their ability to penetrate the cell membrane. For example, glucose and urea are small molecules and can easily pass through the membrane, causing osmosis to occur. In contrast, NaCl, ammonium chloride, and larger molecules may not pass through as easily and lead to different osmotic effects on RBCs.