Assume seawater is a solution of 0.570 M NaCl. Calculate the minimum pressure required at 10.00°C to desalinate seawater so that it contains no more than 177 mg NaCl per liter.

The minimum pressure required is 13.2 atm.

Explanation:

P = ∆CRT

Initial concentration of NaCl in sea water = 0.570 M

Final concentration of NaCl in sea water = concentration in g/L ÷ MW = 177 mg/L × 1 g/1000 mg ÷ (58.5 g/mol) = 0.00303 mol/L = 0.00303 M

∆C (change in concentration of NaCl in sea water) = 0.57 - 0.00303 = 0.56697 M

R is gas constant = 0.082057 L.atm/mol.K

T is temperature = 10 °C = 10+273 = 283 K

P (pressure) = 0.56697×0.082057×283 = 13.2 atm

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