An aqueous dextrose solution having a density of 1.04 g/cm³ freezes at -1.15°C. Find the osmotic pressure of this solution at 25°C.K_f of water is 1.86 °C/m; molecular mass of dextrose = 180.16 g/mol. A)13.8 atm B)14.1 atm C)15.1 atm D)12.9 atm E)120 atm

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Quizplus · Accepted Answer

The freezing point depression is used to find the molality of the solution. ΔTf = i * Kf * m, where ΔTf = 1.15°C, i = 1 (since dextrose is a non-electrolyte), and Kf = 1.86°C/m. Solving for m gives m = 0.618 mol/kg. Using the density, convert molality to molarity: M = m * density = 0.618 mol/kg * 1.04 kg/L = 0.643 mol/L. The osmotic pressure (π) is given by π = MRT, where R = 0.0821 L·atm/mol·K and T = 298 K. π = 0.643 mol/L * 0.0821 L·atm/mol·K * 298 K = 14.1 atm.

An Aqueous Dextrose Solution Having a Density of 1