Question

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_ip, where 

P_i = partial pressure of i^th gas, χ_i = mole fraction of i^th gas in gaseous mixture

(2) p_i = χ_ip_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 = p₁ + p₂ + p₃ 

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