# Does Water With Salt Boil Faster Than Plain Water?

Water with salt in it takes more energy to reach boiling point, so it is likely to take longer to boil when the same volume and surface area of water is heated at the same rate.

This is because the salt dissolves in the water to form a solution containing sodium and chloride ions.

The sodium and chloride ions are electrostatically attracted to the water molecules, making the water molecules more inclined to "stick together". This makes it harder for the water molecules to enter gas phase (which is what happens when water boils).

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The specific heat capacity of salt water is lower than that of plain water, but the boiling point is higher.

The amount of energy required to raise the temperature of 1 kg of plain water from 20°C to its boiling point of 100°C is 4186*80 J = 334,880 J.

The amount of energy required to raise the temperature of 1 kg of water with 35 g of salt added from 20°C to its boiling point of 100.56°C is 1.035*3993/1.0106*80.56 = 329,440 J. That's about 1.6% less heat energy.
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Of course, boiling the water requires supplying the latent heat of vaporization in addition to supplying heat to raise the temperature. In a short search, I could find no data on the difference between salt water and plain water with respect to the heat of vaporization. It is on the order of 2260 kJ/kg.

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Anonymous commented
I rated your answer high because I was impressed with your calculations, but now I'm not sure I agree with it!! There seems to be quite a bit of disagreement on the web over this one. Here's one that disagrees with yours on "Ask a Scientist": Http://www.newton.dep.anl.gov/askasci/phy00/phy00618.htm
Yes the boiling point of salt water is higher due to the structure-making presence of ions,
But the question is not about temperature - it's about time .... Can you make your calcs clearer pls?
Oddman commented
It is also about definition. You need to define what it is that you are boiling and what boiling means. I have calculated the energy required to raise the temperature of 1 kg of water to the boiling point. Less energy requires less time, if energy is transferred at a constant rate. Note that the difference is quite small--<5 seconds out of 5 minutes.
Oddman commented
Your "ask the scientist" reference seems to be right about the facts that
- an open pot of water on the stove is not a controlled experiment
- the relevant numbers all change with temperature and concentration.
He seems to be wrong about the specific heat capacity, which seems to be smaller for salt water at room temperature, even though salt is added. Vapor pressure figures into it, too, depending on how you define "boiling."
The salt water seems to boil faster than the plain water because salt has more sodium than plain water so when I worked on the experiment my hypothesis seem to be right
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Salt does make water boil faster because it makes the humidity thing rise to the top, causing the water to boil faster!
I AM RITE  so don't bother
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It would be plain water because according to tests plain water beats salt water by 10 seconds
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Oddman commented
I would be interested in the details of your experiment and what you did to make sure the amount of salt was the only variable.
Plain water boils faster
than the water with salt
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According to the tv show mythbusters salted water boils slower than plain water
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I think that salt would make the water boil faster because it would to take more room in the pot that is why I think that salt would make water faster.
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The salt water will boil faster than plain or the both of them might boil at the same time
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Yes it does
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