Explain how Avogadro hypothesis used to derive the value of atomicity.

1.	Explain how Avogadro hypothesis used to derive the value of atomicity.
Answer» SOLUTION :(i) The Avogadro.s law states that ..equal volumes of all gases under similar conditions of temperateure and pressure contain equal number of molecules... (ii) LET us consider the reaction between hydrogen and chlorine to form hydrogen chloride gas. `underset("1 volume")(H_(2(g)))+underset("1 volume")(Cl_(2(g)))rarr underset("2 volumes")(2HCl_((g)))` (iii) ACCORDING to Avogadro.s law, 1 volume of any gas is occupied by ..n.. number of molecules. `..n.." molecules"+..n.." molecules"rarr "..2N.. molecule"` If `..n.. = 1`, then `"1 molecule "+"1 molecule"rarr"2 molecules."` `1//2" molecules"+1//2" molecule"rarr"1 molecule"` (iv) 1 molecule of hydrogen chloride gas is made up of `1//2` molecule of hydrogen and `1//2` molecule of chlorine. (v) `1//2` molecule of hydrogen contains 1 atom. So, 1 molecule of hydrogen contains 1 atoms. So, 1 molecule of hydrogen contains 2 atoms. So, hydrogen atomicity is 2. Similarly chlorine atomicity is also 2. So, `H_(2) and Cl_(2)` are diatomic molecules.

Discussion