Question

Wastewater discharged into a stream by a sugar refinery contains 1.70 g of sucrose (C12H22O11) per liter. A government-industry project is designed to test the feasibility of removing the sugar by reverse osmosis. What pressure must be applied to the apparatus at 20.°C to produce pure water?

Answer 1

Answer:

A pressure value more than 0.012 atm must be applied to the apparatus at 20.0°C to produce pure water.

Explanation:

When pressure more than the value of osmotic pressure of the solution is applied to the solution then water will move out from the solution which is termed as reverse osmosis.

Given that 1.70 grams of sucrose was present in 1 L of solution.

Moles of sucrose present in 1 liter of solution  = $\frac{1.70 g}{342 g/mol}=0.004971 mol/L$

C = 0.004971 mol/L

Temperature of the solution = T = 20.0°C = 20.0+273 K = 293 K

Osmotic pressure of soluion = $\Pi$

$\Pi=CRT$

$\Pi=0.004971 mol/L\times 0.0821 atm L/mol K\times 293 K=0.012 atm$

A pressure value more than 0.012 atm must be applied to the apparatus at 20.0°C to produce pure water.