Consider the following halides: $(1) \; BCl_3$,$(2) \; AlCl_3$,$(3) \; GaCl_3$,$(4) \; InCl_3$. What is the decreasing order of their Lewis acid strength?

Which of the following is a true alum?

Observe the following reactions (not balanced):
$BF_3 + LiAlH_4 \xrightarrow{(C_2H_5)_2O} X + LiF + AlF_3$
$X + NaH \longrightarrow Y$
The incorrect statement about $Y$ 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.

Aqueous solution of which of the following boron compounds will be strongly basic in nature?

Give the origin and occurrence of group $13$ elements.