Question

what will happen if animal cell is placed in hypotenic solution​

Answer 1

Hypotonic solutions have more water than a cell. Tapwater and pure water are hypotonic. A single animal cell ( like a red blood cell) placed in a hypotonic solution will fill up with water and then burst. This is why putting water on a bloodstained piece of clothing makes the stain worse.

Answer 2

Cell will gain water and burst if it gains more than enough

This happens because of osmosis (movement of water from low to high percentage of water)