Which of the following oxides is amphoteric in nature?

Identify the incorrect statement about the oxidation states of group $14$ elements.

Which of the following halides is the most stable?

The number of ionisable hydrogens present in the product obtained from a reaction of phosphorus trichloride $(PCl_3)$ and phosphonic acid $(H_3PO_3)$ is

Select the member$(s)$ of group $14$ that $(i)$ forms the most acidic dioxide,$(ii)$ is commonly found in $+2$ oxidation state,$(iii)$ used as semiconductor.

The group $14$ elements $A$ and $B$ have the first ionisation enthalpy values of $708$ and $715 \ kJ \ mol^{-1}$ respectively. These values are the lowest among their group members. The nature of their ions $A^{2+}$ and $B^{4+}$ respectively is: