Question

0.76 g of glucose (molecular mass = 180 g mol⁻¹) is dissolved in 20 ml of aqueous solution at 298 K (R = 0.0821 L atm K⁻¹ mol⁻¹).

What is the osmotic pressure of solution at 298 K?

Options

• 8.41 atm

• 0.48 atm

• 4.41 atm

• 5.16 atm

Answer 1

5.16 atm

Explanation:

Given: Mass of glucose = 0.76 g

Molar mass of glucose = 180 g/mol

Volume of solution = 20 mL = 0.020 L

R = 0.0821 L atm K⁻¹ mol⁻¹

T = 298 K

Moles of glucose (n) = `0.76/180`

= 0.00422 mol

Molarity (M) = `0.00422/0.020`

= 0.2111 mol/L

By using van’t Hoff equation

π = MRT

= 0.2111 × 0.0821 × 298

= 5.16 atm