In which of the following molecules is a hydrogen bridge bond present?

On adding ammonium hydroxide solution to $Al_2(SO_4)_3$ (aq) :

Identify the correct statements from the following:
$(a)$ In orthoboric acid, boron is in planar geometry.
$(b)$ In $BCl_3 \cdot NH_3$, boron has tetrahedral geometry.
$(c)$ Aqueous solution of borax is acidic.

Match the following compounds in List-$I$ with their uses in List-$II$:

List-$I$ (Compounds)	List-$II$ (Uses)
$A$. Boron-$10$	$I$. Antiseptic
$B$. Borax	$II$. Bullet proof vest
$C$. Boron-fibre	$III$. Neutron absorber
$D$. Orthoboric acid	$IV$. Heat resistance glasses

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 one of the following forms a basic oxide?