Which of the following structures is similar to graphite?

Which of the following will not give a borax bead test?

The correct statement$(s)$ for orthoboric acid $(H_3BO_3)$ is/are:
$(A)$ It behaves as a weak acid in water due to self-ionization.
$(B)$ Acidity of its aqueous solution increases upon addition of ethylene glycol.
$(C)$ It has a three-dimensional structure due to hydrogen bonding.
$(D)$ It is a weak electrolyte in water.

Write balanced equations for :
$(i) \, BF_{3} + LiH \to $
$(ii) \, B_{2}H_{6} + H_{2}O \to $
$(iii) \, NaH + B_{2}H_{6} \to $
$(iv) \, H_{3}BO_{3} \xrightarrow{\Delta }$
$(v) \, Al + NaOH \to $
$(vi) \, B_{2}H_{6} + NH_{3} \to $

Why is boric acid considered as a weak acid?

Discuss the pattern of variation in the oxidation states of $(i)$ $B$ to $Tl$ and $(ii)$ $C$ to $Pb$.