The reason for boric acid being polymeric is .....

Hybridisation of boron in diborane is

The reactivity of borazole is higher than that of benzene because ...

$Na_2B_4O_7 \cdot 10H_2O \xrightarrow{\text{Heat}} X + NaBO_2 + H_2O$,$X + Cr_2O_3 \xrightarrow{\text{Heat}} \underset{(\text{Green coloured})}{Y}$. $X$ and $Y$ are

Assertion : Boron is a metalloid.
Reason : Boron shows metallic nature.

Which of the following is an amphoteric oxide?