Avogadro’s law is valid under conditions of ____

Equal volumes of all the gases contain equal number of molecules under identical condition of temperature and pressure.  The molar volume of a gas at a given temperature and pressure is a specific constant.  It is independent of the gas taken

$\mathrm{V\alpha n} \left(\mathrm{or}\right) \left(\mathrm{At} \mathrm{constant} \mathrm{P} \mathrm{and} \mathrm{T}\right)$

$\frac{{\mathrm{V}}_1}{{\mathrm{n}}_1}=\frac{v_2}{n_2}$