Which of the following statements is true about the `14^(th)` group elements ?

Options

A. The stability of their dihalides increases steadily in the order `:PbX_(2) lt SnX_(2) lt GeX_(2) lt SiX_(2)`.
B. The tendency of the elements to catenation decreases as `C gt Si gt Ge ~~ Sn gt Pb`
C. Both `[SiF_(6)]^(2-)` and `[SiCl_(6)]^(2-)` are known.
D. Silica is inert towards `NaOH` but it is attacked by HF forming `SiF_(4)`.

Answer

2

Explanation

`(1)` Correct order is `SiX_(2) lt GeX_(2) lt SnX_(2) lt PbX_(2)` on account of inert pair effect.
`(2)` Bond enthalpy `: " "C-C=348KJ mol^(-1)" "," "Si-Si=297KJ mol^(-1)`
`" "Ge-Ge=260KJ mol^(-1)" "," "Sn-Sn=240KJ mol^(-1)`
`(3)` `[SiF_(6)]^(2-)` existsbut `[SiCl_(6)]^(2-)` does not exist as smaller `Si` can not accomodate six larger chloride ions.
`(4)` `SiO_(2)+2NaOH rarr Na_(2)SiO_(3)+H_(2)O, SiO_(2)+4HF rarr SiF_(4)+2H_(2)O`