# The osmotic pressure of $0.1\;M$ sodium chloride solution at $27^{\circ}C$ is

$\begin{array}{1 1} 4.0\;atm \\2.46\;atm \\ 4.92\;atm \\ 1.23\;atm \end{array}$

Answer : $4.92\;atm$
Osmotic pressure $\pi =cRT=(2 \times 0.1 \;mol\;L^{-1})(0.082\;atm\;LK^{-1}\;mol^{-1})(300 K) =4.92 \;atm$
Why have you considered C = [ 2 (0.1) mol/L]