Which one is not correct mathematical equation for Dalton's law of partial pressure? Here p = total pressure of gaseous mixture

(1) p_{i }= χ_{i}p, where

P_{i} = partial pressure of i^{th }gas, χ_{i} = mole fraction of i^{th }gas in gaseous mixture

(2) p_{i }= χ_{i}p_{i}°, where

χ_{i =} mole fraction of i^{th} gas in gaseous mixture, p_{i}° = pressure of i^{th} gas in pure state

(3) p = p_{1} + p_{2 }+ p_{3}

(4) $p = n_1{RT\over V}+n_2{RT\over V}+n_3{RT\over V}$^{}^{}