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

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$ : Boric acid is a weak acid.
Reason $R$ : Boric acid is not able to release $H^{+}$ ion on its own. It receives $OH^{-}$ ion from water and releases $H^{+}$ ion.
In the light of the above statements,choose the most appropriate answer from the options given below.

Orthoboric acid in aqueous medium is

In group $13$ of the long form of the periodic table, an element $X$ has a boiling point of $T_2 \ (K)$ and a melting point of $T_1 \ (K)$. Identify the element $X$ for which $T_2 - T_1 \ (K)$ is maximum.

The covalency and oxidation state respectively of boron in $[BF_4]^-$ are

Which of the following imparts a green colour to the burner flame?