A certain mass of gas A is kept in a closed container where it undergoes dimerisation, according to the reaction : 2 ~A ( ~g ) A ₂( ~g ) Assuming temperature to remain constant, it was found that the partial pressure of A ₂ gas after time t was one-fifth of the initial pressure in container. Then, select the correct statement(s) :

Step-by-step solution

aligned & array l &2 A ~ &A₂ t=0 &n &0 t=t &n-x &x/2 array & P moles P_i n = P_f n- x 2 ~...(1) aligned Also, from Dalton's law, p _ A ₂ = X _ A ₂ P _ f p _ A ₂ = ( x 2 n- x 2 ) P_f ~...(2) And, p _ A ₂ = 1 5 P _ i ~...(3) From equations (1), (2) and (3), aligned & x= 2 n 5 P_i P_f = n n- x 2 = n n- n 5 = 5 4 & X_ A₂ = ( x 2 n- x 2 )= n / 5 4 n / 5 =0.25 aligned % dimerisation = x n 100= 2 n / 5 n 100=40 % Mol. mass of A=10⁻²² 6 10²³=60 amu aligned & M_ avg. = n _ A M _ A + n _ A ₂ M _ A ₂ n _ A + n _ A ₂ & = 3 n 5