Question

The osmotic pressure of a solution of an organic substance containing 18 gm in 1 lit of solution at 293 K is $2.414\times {10}^5{Nm}^{-2}$. Find the molecular mass of the substance. If S= 8.3 J$K^{-1}{mole}^{-1}$

• A. $181.55$
• B. $362.66$
• C. $36.2$
• D. $18.1$

Answer 1

The correct option is A $181.55$

$\pi =2.414\times {10}^{5}N/m^2$

$=2.382atm$

$S=8.3J{K}^{-1}mol{e}^{-1}=0.0821lit.atm/K.mole$

$\pi =C_{M}RT(R\to S)$

$2.382=\frac{18}{Mwt}\times 1\times 293\times 0.0821$

$M\omega t=\frac{18\times 293\times 0.0821}{2.4382}$

$=181.55g/mole$

Option A is correct.