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Which of the following statements is true about the `14^(th)` group elements ?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)`. |
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Answer» Correct Answer - 2 `(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` |
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