1 L of a gaseous element reacts with 2 L of another gaseous element to form 1 L of a gaseous compound (all volumes being measured under identical conditions of temperature and pressure). If both the element are diatomic and their symbols are X and Y respectively, then what will be the molecular formula of the compound.

Explanation

Here, 1L of X combines with 2L of Y to form 1L of a gaseous compound. Let, n be the number of molecules present per litre of the gas under the same temperature and pressure.
So according to Avogadro's hypothesis,
n molecules of X react with 2n molecules of Y to form n molecules of gaseous product.
i.e., 1 molecule of X+2 molecules of Y=1 molecule of the gaseous product
or, 2 atoms of X+4 atoms of Y=1 molecules of the gaseous compound [since the reactants are diatomic]
`therefore` Molecular formula of the compound is `X_(2)Y_(4)`.