Which of the following represents the structure of inorganic benzene?

When $B_2H_6$ reacts with excess $NH_3$ at a very high temperature $(> 200 \, ^\circ C)$,the product formed is:

The correct statements among $I$ to $III$ regarding group $13$ element oxides are,
$I$. Boron trioxide is acidic
$II$. Oxides of aluminium and gallium are amphoteric
$III$. Oxides of indium and thallium are basic

Select the incorrect statement:
$a$. $PCl_5$ forms a weak monobasic acid during hydrolysis.
$b$. In $B_3N_3H_6$,nucleophilic attack occurs on the $B$ atom.
$c$. $Al_2Cl_6$ is a polar and planar molecule.
$d$. In $AlF_3$,the hybridization of $Al$ is $sp^2$.

Give the physical and chemical properties of orthoboric acid $(H_3BO_3)$.

Consider the following statements for diborane $(B_2H_6)$:
$1.$ Boron is approximately $sp^3$ hybridized.
$2.$ $B-H-B$ angle is $180^{\circ}$.
$3.$ There are two terminal $B-H$ bonds for each boron atom.
$4.$ There are only $12$ bonding electrons available.
Which of these statements are correct?