`CNS^(ө)` ions give red colour with `Fe^(3+)` ions in aqueous solution as:
`Fe^(3+)(aq) + 3CNS^(ө)(aq) rarr Feunderset("red")((CNS))_(3)(aq) `
If `0.1 M` `KCNS` solution is separated from `0.1 M FeCl_(3)` solution by means of a semi-permeable membrane, red colour will appear on:
a.`FeCl_(3)` soluion , b. `KCNS` solution side ,
c. Both sides , d. Neither side

Explanation

d. `Fe^(3+)(aq) + 3CNS^(ө)(aq) rarr Feunderset("Red")((CNS))_(3)(aq)`
`rArr` Only solvent molecules moves from dilute solution to concentrated solution.
`{:(underset("(Dilute)")(underset(C_("effective")=0.2 M)(0.1MKCNS)),,,underset(C_("Concentrated"))underset(C_("effective")=0.2M)(0.1MFeCl_(3))):}`
So , no red color will appear.