The maximum number of atoms present in the same plane in diborane molecule is :

$AlC{l}_3$ on hydrolysis gives :

Which of the following elements has the hardest allotropic form?

Name the type of the structure of silicate in which one oxygen atom of ${\left[Si{O}_4\right]}^{4-}$ is shared:

Which one of the following statement is not correct?

Thallous chloride is more stable than thallic chloride because of:

List I	List II
A. Diamond	1. Lubricant
B. Water gas	2. $CO+N_2$
C. Producer gas	3. $CO+H_2$
D. Graphite	4. Abrasive

The aqueous solution of 'A' is alkaline due to

Which of the following specie(s) has/have a tetrahedral structure?

Consider the structure of $A{l}_{2}M{e}_6$ compound and find the value of $\frac{x-y}{z}$, where: 
$x=$ Maximum number of atoms that can lie in plane having terminal $(Al-Me)$ bonds.
$y=$ Total number of $3c-2e^{-}$ bonds.
$z=$ Total number of atoms that are $s{p}^3$ hybridized.