Question

Why does the temperature of substance remain countence during its melting point or boiling point

Answer 1

.


Yes temp is constant at boiling or melting point but upto it get completely get boiles or melt after that temp is increase

Because of phase transition ie from solid to liquid during melting and from liquid to vapour during boiling. So just to change over from one phase to the other heat is totally utilized and hence no chance to have a rise in temperature. So temperature remains constant

Take a example of water

Take a 20lit. water in closed vessel of 293k and start to boil it temp will raise upto 373K after that water start boiled and start to vaporise.

Now when your water is boiling and consider half of water get boiled so now you have 10lit of water at 373k and vapour is also at 373 k because all heat what you supplied goes for water boiling untill it get fully water converted to vapour. When whole 20 lit of water will convert in vapour then vapour temp start to increase upto which temp is constant at373 k

So temp in boiling process is constant