Which element among the following has the maximum bond energy?

$H_2S$ gas changes a filter paper dipped in lead acetate solution into

Which of the following is not correct?

Which of the following oxides reacts with both $HCl$ and $NaOH$?

The correct statements with respect to halides of group $14$ elements are:
$I$. Both $CCl_4$ and $SiCl_4$ undergo hydrolysis
$II$. $GeX_4$ is more stable than $GeX_2$
$III$. $PbX_4$ is less stable than $PbX_2$
$IV$. Stability of dihalides decreases down the group.

The least stable hydride is: