Which gas is highly soluble in water?

$A$ metal $M$ does not liberate hydrogen from acids but reacts with oxygen to give a black coloured product. Identify $M$ and the black coloured product,and also explain the reaction of $M$ with oxygen.

Define alloys. List the properties of alloys that make them useful over pure metals. Explain this fact with suitable examples.

Bronze is an alloy of:

Give the formulae of the stable binary compounds that would be formed by the combination of the following pairs of elements:
$(a)$ $Mg$ and $N_{2}$
$(b)$ $Li$ and $O_{2}$
$(c)$ $Al$ and $Cl_{2}$
$(d)$ $K$ and $O_{2}$

Which metal can be beaten into very thin foils?