Question

what happens to an animal cell when it is placed in a very dilute external medium

Answer 1

When an animal cell is placed in a very diluted external medium, it gains water by the process of osmosis. As a result, the cell swells up and can sometimes burst as animal cells do not have cell walls.

Answer 2

Every solution has two components, solute (sugar, salt etc.) and solvent (water). The solute dissolves in the solvent and forms a solution. Here the animal cell is kept in dilute external medium that means hypotonic solution. Hypotonic solution: In this solution the solute concentration is lower than that of the cell fluid concentration. As a result, water moves into the cell from the surrounding medium through a cell membrane. This results in causing the cell to swell and burst.