When 100ml of 0.06M Fe(NO)₃, 50ml of 0.2M FeCl₃ and 100ml of 0.26M Mg(NO₃)₂, are mixed; the concentration of NO₃^- ions in the final solution is

Mixture of solutions contain

A) 100ml of 0.06M Fe(NO₃)₃

B) 50ml of 0.2M FeCl₃

C) 100ml of 0.26M Mg(NO₃)₂

${\mathrm{NO}}_3^{-}$ ions are present only in solution (A) and solution (C)

Solution(A) [Fe(NO₃)₃]

${\mathrm{n}}_{{\mathrm{NO}}_3^{-}}$(from ferricnitrate) =6$\times$10^-3$\times$3

Solution(C) [Mg(NO₃)₂]

${\mathrm{n}}_{{\mathrm{NO}}_3^{-}}$ [from Mg(NO₃)₂] =0.026$\times$2= 0.052

Total moles of ${\mathrm{NO}}_3^{-}$ions in the mixture =(18$\times$10^-3) + 0.052= 0.07

Total volume of solution = (100 + 50 + 100)ml = 250ml

${\mathrm{M}}_{{\mathrm{NO}}_3^{-}}$in the mixture =$0.07\times \frac{1000}{250}=0.28 \mathrm{M}$