Boiling point of NaCl and KCl

Practice Question Solving
1

Solution A contains 1 mole of sodium chloride in 1 lite of wats? Solution B contains 1 mole of
potassium chlorice in 1 lite of water. Both solutions are heated and the boiling point is measured.
Which of the following statements is correct ?

A) Solution A has a higher boiling point
B) Solution B has a higher boiling point
C) Both of solutions will have the same boiling point
D) More information is required to determine the relative boiling points

The answer is C. Why do.p they both have the same boiling points?

2

Hi!

I believe that for a solution the boiling point just depends on the concentration of solute and the number of particles they form
they both have the same concentration, and NaCl ---- Na⁺ + Cl⁻, KCl — K⁺ + Cl⁻ so they both give off the same number of particles
So they must have the same boiling point

Hope this helps!!!

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3

Why does the concentration of the solution impact the boiling point?

4

Pure water has a boiling point of 100 however as you add salt to it, it makes it harder for the water molecules to escape from the pot and enter the gas phase. The more salt you add, the harder it is. So the boiling point increases with the concentration. Hope this helps!!

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5

Why does it become harder for the water molecules to escape from the pot to become gas?

6

boiling point is the vaporisation of water :slight_smile: As salt dissolves into water, some water molecules at the surface are replaced by Na+ or K+ and Cl- ions hence vapourization of water DROPS! that means you have to put more energy to vaporize it to the earlier same level - in other words, boiling point increases! It’s known as a colligative property as only the quantity of salt affects it and not the nature. Does this help? :))

7

Yes! Thank you so much!!!

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