If the formula of Borax is $Na_2B_4O_x(OH)_y \cdot zH_2O$,then $x+y+z = ...........$.

Three pairs of compounds are given below. Identify the compound in each pair which has the group $13$ element in a more stable oxidation state. Give reasons for your choice and state the nature of bonding. $(A)$ $TlCl_3, TlCl$ $(B)$ $AlCl_3, AlCl$ $(C)$ $InCl_3, InCl$

Borax is used as a cleansing agent because on dissolving in water it gives:

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.

Which of the following is the weakest acid?

Identify the correct statements from the following:
$a$) Borax gives blue coloured $Co(BO_2)_2$ when heated with $Co^{2+}$ salt.
$b$) The correct formula of Borax is $Na_2[B_4O_5(OH)_4] \cdot 8H_2O$.
$c$) Trihalides of boron are Lewis bases.