Question

A solution of sucrose (molar mass = 342 g/mol) is prepared by dissolving 68.4 g of it per litre of the solution. What is its osmotic pressure (R = 0.082 lit. atm.k^-1mol^-1) at 273 K?

• A. 6.02 atm
• B. 4.92 atm
• C. 4.04 atm
• D. 5.32 atm

Answer 1

Answer: (B)

Weight given (sucrose) = 68.4 gram

Gas constant (R) = 0.082 lit. atm.$K^{-1}$ ${mol}^{-1}$

Temperature = 273 K

Molecular mass = 342 gm/mol

V = 1

Hence using the formula of osmotic pressure we get

$\pi =\frac{w\times R\times T}{molarmass\times Volume}$

$\pi =\frac{68.4\times 0.082\times 273}{342}$

$\pi =4.48atm$