Question

A solution contains non volatile solute of molecular mass M2. Which of the following can be used to calculate the molecular mass of solute in terms of osmotic pressure

• A. M2=($\frac{m_2}{\pi}$)VRT
• B. M2=$(\frac{m_2}{V})\frac{RT}{\pi}$
• C. M2=$(\frac{m_2}{V})\pi RT$
• D. M2=$(\frac{m_2}{V})\frac{\pi}{RT}$

Answer 1

Answer: (B)

M2=$(\frac{m_2}{V})\frac{RT}{\pi}$

Answer 2

The correct option is (B) : M2=$(\frac{m_2}{V})\frac{RT}{\pi}$

For dilute solution, pV=nRT or $\pi$V=nRT or $\pi$V= $\frac{m_2}{M_2}$ RT or M2 = $\frac{m_2}{\pi V}$ RT ​where, $\pi$ = osmotic pressure V =volume of solution n = number of moles of solute m2=mass of solute M2= molecular mass of solute