Which of the following oxides is acidic in nature?

Give the chemical reaction of aluminum with dilute $HCl$.

Sodium borate on reaction with $H_2SO_4$ (conc.) and $C_2H_5OH$ gives a compound '$A$' which burns with a green flame. The compound '$A$' is

$A$ Lewis acid '$X$' reacts with $LiAlH_{4}$ in ether medium to give a highly toxic gas. This gas when heated with $NH_{3}$ gives a compound commonly known as inorganic benzene. The gas is

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:

Hybridisation of boron in diborane is