Which element belongs to the family of elements that also includes the element gallium?

Two elements $X$ and $Y$ react with highly electropositive metals to form binary compounds,which upon hydrolysis yield borane and silane,respectively. What are $X$ and $Y$?

Name the metals with which $Al$ can form alloys.

Borax dissolves in water and forms a product of boron $(X)$. Identify the compound $X$.

$A$ 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

The correct order of Lewis acidic character of boron trihalides is