Which of the following is the most basic oxide?

Identify the correct statement for $B_2H_6$ from those given below.
$(A)$ In $B_2H_6$,all $B-H$ bonds are equivalent.
$(B)$ In $B_2H_6$ there are four $3$-centre-$2$-electron bonds.
$(C)$ $B_2H_6$ is a Lewis acid.
$(D)$ $B_2H_6$ can be synthesized from both $BF_3$ and $NaBH_4$.
$(E)$ $B_2H_6$ is a planar molecule.
Choose the most appropriate answer from the options given below.

In borax, the number of $B-O-B$ links and $B-OH$ bonds present are, respectively:

$STATEMENT-1$: In water,orthoboric acid behaves as a weak monobasic acid. because
$STATEMENT-2$: In water,orthoboric acid acts as a proton donor.

Explain the structures of diborane and boric acid.

Sodium borate on reaction with $H_2SO_4$ (conc.) and $C_2H_5OH$ gives a compound '$A$' which burns with a green flame. The compound '$A$' is