State and explain van't Hoff-Avogadro's law.

Explanation

Statement of van't Hoff-Avogadro's law : At given temperature, equal volumes of the solutions having the same osmotic pressure contain equal number of solute particles.
Explanation: One mole of a substance contains Avogadro's number of molecules (i.e., `6.02 xx 10^(23)` molecules). Therefore, the equal number of moles of the substances will contain equal number of molecules.
The osmotic pressure, `pi` , is given by `pi` = CRT
where C is the concentration of a solution in mol `dm^(-3)`.
`pi - (n)/(v) RT`
`therefore pi prop (n)/(V)` at constant temperature.
If two solutions contain `n_(A)` and `n_(B)` moles of two solutes in the equal volumes (V) of the solutions A and Bat the same temperature, then `pi_(A) prop n_(A//V)`
and `pi_(B) prop n_(B//V)`
`therefore (pi_(B))/(pi_(A)) =(n_(A))/(n_(B))`
If `pi_(A) = pi_(B)` , then
`n_(A) = n_(B)`