Question

You prepare a 5.87 m solution of sodium chloride, nacl (table salt) to cook your pasta. its density is 1.27 g/ml. At what temperature will it boil (assume that your kitchen is at sea level, and treat your atmospheric pressure as exactly 1 atm.)?

Answer 1

The boiling temperature of a 5.87 m sodium chloride solution at sea level and 1 atm pressure would be approximately 106.01 °C. Sodium chloride causes a boiling point elevation due to its ability to dissociate into two ions upon dissolving. This effect, although resulting in a higher boiling temperature, does not significantly affect pasta cooking times.

Step-by-step explanation:

The subject of this question is boiling point elevation in sodium chloride (NaCl) solutions, which is a colligative property of solutions in chemistry. To determine the boiling temperature of a 5.87 m solution of sodium chloride, we utilize the formula for boiling point elevation, ΔTb = i * Kb * m, where ΔTb is the change in boiling point, i is the van 't Hoff factor (which is 2 for NaCl, because it dissociates into two ions: Na+ and Cl-), Kb is the ebullioscopic constant of water (0.512 °C/m), and m is the molality of the solution. Since 1 mol of NaCl raises the boiling point by 2 * 0.512 = 1.024 °C, a 5.87 m solution would raise the boiling point by 5.87 * 1.024 °C = 6.0118 °C. Considering that the boiling point of pure water at sea level is 100 °C, the sodium chloride solution would boil at approximately 106.01 °C, given that it is a 5.87 m solution at 1 atm pressure. This temperature increase, while making the water boil at a higher temperature, has a negligible effect on cooking times for pasta.