The functional groups that are responsible for the ion-exchange property of cation and anion exchange resins, respectively, are:

x      +      y    +   3z     =     xyz₃

1 mole 1 mole 0.05 mole

$\therefore n_x=1$

$n_y=1$

$n_z=\frac{0.05}{3}=0.0167$  here z is limiting reagent.

$?\frac{0.05}{3}$  mole z gives 1 mole xyz₃

mass of xyz₃ = n × molecular mass

=  $\frac{0.05}{3}\times \left(10+20+3\times 30\right)a.m.u.$  

= 0

Molar mass of C₇H₅N₃O₆ = 12 × 7 + 1 × 5 + 14 × 3 + 16 × 6 = 84 + 42 + 96 = 227 g/mol

Number of moles =  $\frac{681}{227}$  = 3 mol

$\therefore$  number of N-atoms

$=3\times 6.02\times 10^{23}\times 3=9\times 6.02\times 10^{23}$  

$=5418\times 10^{21}$  

$\therefore x=5418$  

-SO? H acts as a cation exchanger.

-NH? acts as an anion exchanger.