Question

utions 21. Use the solubility curve for sodium nitrite, NaNO2, to of the st swer the following question. A solution is prepared by dissolving 60 kg of sodium nitrite in 50 kg of water at 80 °C and the resulting solution is cooled to 30 °C Which of the following is true? ion In. 28 on eak ong e 20 80 60 40 TemperatureC A. The cooled solution is unsaturated. B. 90 kg of sodium nitrate is contained in the cooled ns solution. 60 kg of sodium nitrate is contained in the cooled C. (D, solution. sodium nitrate įs contained in the cooled E. The amount of solute in solution cannot be determined

Answer 1

From graph

Solubility of NaNO₃ at 80^oC = 135 g /100 g water

Thus, in 50 g of water, solubility is 135/2 = 67.5 g\

Dissolved amount = 60 g

Thus, solution is unsaturated and whole NaNO₃ will be dissolved

At 30^oC, solubility = 90 g/100g water

So, In 50 g of water, solubility = 90/2 = 45 g

Thus, in cooled solution, 45 g of NaNO₃ and 15 g will precipitate out and solution becomes supersaturated