Each of the following is a $0.10\mathrm{M}$ solution at $300\mathrm{K}$. With $R=0.0821\mathrm{L}\mathrm{atm}\mathrm{mo}{\mathrm{l}}^{-1}{\mathrm{K}}^{-1}$, which have an osmotic pressure greater than $4.0$ atm? (For $\pi =iCRT$ use $i=1+(n-1)\alpha$.)

1. A$\mathrm{NaCl}$, fully dissociated ($\alpha =1$)
2. B$\mathrm{K}{}_2\mathrm{SO}{}_4$, $\alpha =0.40$ ($n=3$)
3. CUrea
4. DAcetic acid, $\mathrm{CH}{}_3\mathrm{COOH}\rightleftharpoons \mathrm{CH}{}_3\mathrm{COO}{}^{-}+\mathrm{H}{}^{+}$, $\alpha =0.010$