Explain what happens when boric acid is heated.

(N/A) On heating orthoboric acid $(H_3BO_3)$ at $370 \, K$ or above,it loses a water molecule to form metaboric acid $(HBO_2)$.
On further heating at red heat,it loses more water to yield boric oxide $(B_2O_3)$.
The reactions are as follows:
$H_3BO_3 \xrightarrow[370 \, K]{\Delta} HBO_2 + H_2O$
$2HBO_2 \xrightarrow[red \, hot]{\Delta} B_2O_3 + H_2O$