Which type of oxide is $CO_{2}$?

$A$ metal $A$,which is used in the thermite process,when heated with oxygen gives an oxide $B$,which is amphoteric in nature. Identify $A$ and $B$. Write down the reactions of oxide $B$ with $HCl$ and $NaOH$.

Write equations for the reactions of:
$(i)$ Iron with steam
$(ii)$ Calcium and potassium with water

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:

$(a)$ When calcium metal is added to water,the gas evolved does not catch fire,but the same gas evolved on adding potassium metal to water catches fire. Explain why?
$(b)$ Name a metal for each case:
$(i)$ It displaces hydrogen gas from nitric acid.
$(ii)$ It does not react with any physical state of water.
$(iii)$ It does not react with cold as well as hot water but reacts with steam.

State whether the following statement is true or false:
Copper does not burn in air, but the hot metal is coated with a black-coloured layer of copper $(II)$ oxide.