The reason for the polymeric nature of boric acid is .....

Assertion $(A)$: $[B(OH_2)_6]^{3+}$ and $[B(OH)_4]^{-}$ form octahedral and tetrahedral structures.
Reason $(R)$: Being electron deficient, boron readily reacts with Lewis bases like $H_2O$ and $OH^{-}$.
The correct option among the following is

Which of the following elements does not release $H_2$ gas upon reaction with an acid?

Match the List-$I$ with List-$II$.

List-$I$ (Element)	List-$II$ (Application)
$A$. $Cs$	$I$. High temperature thermometer
$B$. $Ga$	$II$. Water repellent sprays
$C$. $B$	$III$. Photoelectric cells
$D$. $Si$	$IV$. Bullet proof vest

Choose the most appropriate answer from the options given below:

Boric acid,$H_3BO_3$,is a/an ....

What is $Z$ in the following reactions?
$BCl_3 + H_2 \xrightarrow[450^{\circ}C]{Cu-Al} X + HCl$
$X \xrightarrow{\text{methylation}} Z$