JEE Main · 2026 · 04 Apr 2026 · Shift 2 · Solutions

Osmotic pressure depends on the total concentration of dissolved particles, $\pi =iCRT$. With complete dissociation, ${\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6]$ gives $i=5$ (four ${\mathrm{K}}^{+}$ and one $[\mathrm{Fe}(\mathrm{CN}{)}_6{]}^{4-}$), while $\mathrm{FeC}{\mathrm{l}}_3$ gives $i=4$ (one $\mathrm{F}{\mathrm{e}}^{3+}$ and three $\mathrm{C}{\mathrm{l}}^{-}$). At equal concentration and temperature, side $x$ with $i=5$ has the higher osmotic pressure and side $y$ with $i=4$ the lower. A solution of lower osmotic pressure is the hypotonic one, and solvent flows from it toward the stronger solution across the membrane. The correct statement is that the solution on side $y$ is hypotonic.