Which metal burns in air at high temperature with the evolution of much heat?

What does orthoboric acid contain?

Which is not true about borax?

Identify the correct statements:
$i$. Oxidation of $NaBH_4$ with $I_2$ gives $B_2H_6$
$ii$. $B_2H_6$ burns in oxygen and releases an enormous amount of energy
$iii$. $B_2H_6$ on hydrolysis gives a tribasic acid

The element that combines with oxygen to give an amphoteric oxide is

Give the chemical reaction for the preparation of a borax bead.