The tendency of $BF_3, BCl_3$ and $BBr_3$ to behave as Lewis acid decreases in the sequence

The incorrect order of  $1^{st}$  $IP$  of the elements is

The compound($s$) which react($s$) with $NH _3$ to give boron nitride ($BN$) is(are)

$(A)$ $B$ $(B)$ $B _2 H _6$ $(C)$ $B _2 O _3$ $(D)$ $HBF _4$

Borax is actually made of two tetrahedra and two triangular units joined together and should be written as : $Na_2[B_4O_5(OH)_4]·8H_2O$

Consider the following statements about borax :

$a.$  Each boron atom has four $B-O$ bonds

$b.$  Each boron atom has three $B-O$ bonds

$c.$  Two boron atoms have four $B-O$ bonds while other two have three $B-O$ bonds

$d.$  Each boron atom has one $-OH$ groups

Select correct statement(s) :

Is boric acid a protic acid ? Explain. 

Inorganic benzene is