The bursting of a red blood cell placed in a hypotonic solution is called haemolysis. 

A hypotonic solution has a lower solute concentration than the cell's contents. When a red blood cell is placed in a hypotonic solution, water moves into the cell.This causes the cell to swell and eventually burst.The process of a cell swelling and bursting is called haemolysis. 

• Isotonic: An environment where the flow of water in and out of a cell is equal. 
• Osmosis: The movement of water across a semipermeable membrane. Osmosis is important in maintaining homeostasis, which is the tendency of systems toward a relatively stable dynamic equilibrium. 

• Crenation: The process of a red blood cell shrinking in size when placed in a hypertonic solution.