Which of the following is not associated with water molecules?

Which of the following show diagonal relationship?

The type of hybridisation of boron in diborane is

Consider the following flow diagram for the extraction of borax from colemanite:
$2CaO \cdot 3B_2O_3 + Na_2CO_3 \xrightarrow{\text{aq. medium}} Z \text{ (Residue/ppt)} + \text{Filtrate}$
$\text{Filtrate} \xrightarrow{\text{Crystallisation & Filtration}} X \text{ (in filtrate)} + Y \text{ (Residue)}$
$X + CO_2 \to Y$
Identify compounds $X$ and $Y$ respectively.

$BCl_3 + H_2O \longrightarrow$ Product,here product is:

In which of the following does the inert pair effect play a significant role?