Identify the cyclic silicate ion given in the figure below:

Assertion : $SiF_6^{2-}$ is known but $SiCl_6^{2-}$ is not.
Reason : Size of fluorine is small and its lone pair of electrons interacts with $d-$orbitals of $Si$ strongly.

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 are respectively:

For bleaching powder,which of the following statements is incorrect?

How is $H_2S$ liberated in the laboratory?

The formula of Feldspar is: