In atomic reactors,graphite is used as a

Which of the following is an incorrect statement?

$X \xrightarrow{CoCl_2} CaCl_2 + Y \uparrow$; the effective ingredient of $X$ is

The catenation tendency of $C$,$Si$ and $Ge$ is in the order $Ge < Si < C$. The bond energies (in $kJ \ mol^{-1}$) of $C-C$,$Si-Si$ and $Ge-Ge$ bonds,respectively,are:

In which of the following sets are allotropes of carbon correctly matched with their uses?
$i$. graphite - crucibles
$ii$. activated charcoal - water filters
$iii$. carbon black - fuel
The correct answer is

Explain the physical properties of group $14$ elements.