Which of the following properties of $H_2$ (dihydrogen) gas is $NOT$ correct?

An element $A$ forms two oxides $AO$ and $AO_2$. The oxide $AO$ is neutral,whereas the oxide $AO_2$ is acidic in nature. Would you call element $A$ a metal or a non-metal?

Explain the following statements:
$(a)$ Most metal oxides are insoluble in water but some of these dissolve in water. What are these oxides and their solutions in water called?
$(b)$ At ordinary temperature,the surfaces of metals such as magnesium,aluminium,and zinc are covered with a thin layer. What is the composition of this layer? State its importance.
$(c)$ Some alkali metals can be cut with a knife.

Provide one exception for each of the following general statements:
$(i)$ Metals are lustrous.
$(ii)$ Metals are solids at room temperature.
$(iii)$ Metals have high melting points.
$(iv)$ Non-metals are non-lustrous.
$(v)$ Non-metals are insulators or non-conductors of electricity.

Which method/process is used to obtain pure alumina from bauxite?

An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be: