What does water react to?

Question

I need a siple thing that water reacts to. I am doing scinece and it says I gotta determine the identity of unknown substances. Water is one of them. So what does it react with so I can know the difference between it and Rubbing alchohol, viengar, and salt water. Also if you know what those react with that would help. They can't react with the same things, like venegar can't react with whatever I use for water because then I wouldn't know the difference.

Answer 1

Well use a series of steps.

1st step add Calcium Carbonate. This will fizz in the case of the vinegar, as acid plus carbonate gives salt, water and carbon dioxide. U can even test the gas to be CO2, as it turns lime water milky. U will eliminate the vinegar from further tests.

2nd is separate the alcohol from the salt and fresh water. Do this by testing with Cobalt chloride paper. The paper changes from blue to pink if any water is present. The sample which doesn't change the paper would be the alcohol.

3rd is to separate the salt water from the fresh water. Do this by adding silver nitrate followed by aqueous ammonia. Salt contains sodium chloride, so the presence of the Cl- ion will cause the formation of a white precipitate that dissolves in excess alkali.
So, the one that produces no ppt is therefore pure water.

Answer 2

You need to be careful here. You must also remember that rubbing alcohol and vinegar and salt water are not pure substances. They are mixed in water. Water is a dilutant.

One of the posters is correct that sodium or potassium react to water, but not just water. They will also react with salt water, rubbing alcohol and vinegar (as all three contain water).

The easiest way to identify what they are is to slowly evaporate them. Vinegar and salt water will leave a solid behind. Pure water will not. Rubbing alcohol (Isopropyl alcohol) will not because it has a boiling point lower than water. The way to separate those is through distillation. Alcohol will react with things water won't react with. Water is very non reactive whereas all of the other three are more reactive.

Vinegar is an acid and will react with baking soda where water will not.

I think alcohol will react with baking soda as well. I do not know about salt water but believe it could as well. You can test all of these in your kitchen (with parental supervision) if you want to be sure.

To identify water from the other three you are much better off realizing that water does not react to many things that the other three will.

Another way is to try to conduct electricity (small amount) through the liquid. Connect two wires to a dry cell battery (one to each terminal) and put one of the wires in the unknown solution and attach another wire to a small hobby kit light bulb. Then connect the second light bulb connecter to a third wire and put it in the solution as well. Pure water will not light the bulb or will only very dimly. The other three will conduct the electricity way more readily. That is because they have many more free electrons in solution than pure water does.

I hope this helps.

Answer 3

Water reacts to a variety of metals, sodium comes to mind. Whether you will have access to sodium metal and whether you would be permitted to use it is questionable, because the reaction can be fairly violent, and produces hydrogen gas.

One idea for identifying water, is that unlike alcohol (and maybe vinegar - that I'm not sure...) it is a polarized molecule. If you have a stream of water flowing from a tap, and you hold something statically charged (like a balloon that you rub on your head) near it, the stream will slightly deflect.

Vinegar is an acid, so you can use many standard acid tests (phenol phaline maybe? sorry digging back in old memories).

And alcohol is the only one of the above that is flammable.

Answer 4

Water reacts violently with pure sodium. It becomes an explosive mixture.

Answer 5

i'm not too sure but i know that theoretically, pure water reacts more than the water you get out of a tap because it has additives to it... so you could do several tests but not all of them would would necessarily work with tap water... just something to keep in mind...