The plot of osmotic pressure ($\pi$) vs concentration ($ ext{mol L}^{-1}$) for a solution gives a straight li

Question

The plot of osmotic pressure ($\pi$) vs concentration ($	ext{mol L}^{-1}$) for a solution gives a straight line with slope $25.73 	ext{ L bar mol}^{-1}$. The temperature at which osmotic pressure measurement is done is: (Use $R=0.083 	ext{ L bar mol}^{-1} 	ext{ K}^{-1}$)

Accepted Answer

According to the equation for osmotic pressure, $\pi = CRT$, where $\pi$ is osmotic pressure, $C$ is molarity (concentration in $	ext{mol L}^{-1}$), $R$ is the gas constant, and $T$ is temperature in Kelvin .

When a graph is plotted between osmotic pressure ($\pi$) on the y-axis and concentration ($C$) on the x-axis, it gives a straight line with a slope equal to $RT$.

Given slope = $25.73 	ext{ L bar mol}^{-1}$
Therefore, $RT = 25.73$
$T = \frac{25.73}{R} = \frac{25.73}{0.083} = 310 	ext{ K}$

To convert the temperature to Celsius:
$T (^{\circ}	ext{C}) = T (	ext{K}) - 273 = 310 - 273 = 37^{\circ}	ext{C}$.

Hence, the temperature at which the measurement is done is $37^{\circ}	ext{C}$.

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