Question

Why setting of plaster of paris takes place?

Answer 1

Hello Friend !


2 CaSO4*(1/2)H2O + 3 H2O --> 2 CaSO4*2H2O 

Plaster of Paris is a slightly soluble solid which reacts exothermically with water to produce gypsum (CaSO4*2H2O). The reaction happens within minutes of mixing CaSO4*(1/2)H2O with water.


Hope this helps !!

Answer 2

This is because of hydration.