Which of the following gas mixtures is used by divers inside the sea?

Which of the following oxides is amphoteric in nature?

Which one of the following elements reacts with steam?

Two statements are given below.
Statement $I$: $SnF_4$ and $PbF_4$ are ionic in nature.
Statement $II$: $GeCl_2$ is more stable than $GeCl_4$.
The correct answer is:

$(a)$ Classify the following oxides as neutral,acidic,basic,or amphoteric:
$CO, B_2O_3, SiO_2, CO_2, Al_2O_3, PbO_2, Tl_2O_3$
$(b)$ Write suitable chemical equations to show their nature.

Dry ice is