# Do you get a new chemical compound if you mix sodium hydroxide and water?

Me and dad started fighting over this a couple of days ago and wagered on this.

He said mixing these two gives a chemical compound, I said that it doesn't.

• Is what a chemical compound? The mixture? – f'' Aug 7 '16 at 17:36
• Is it a chem compound the mixture of water and sodium hydroxyde. – Alek Aug 7 '16 at 17:41
• Then you are right. NaOH is a compound, so is H2O, but their mixture isn't. – Ivan Neretin Aug 7 '16 at 18:09
• We need the exact sentence for your bet, because it is more tricky than you (and your father) think. – SteffX Aug 7 '16 at 18:21
• How much was the wager? – Todd Minehardt Aug 8 '16 at 1:09

## 2 Answers

According to Oxford's dictionary of chemistry "A compound is a mixture of two or more elements in a fixed ratio". So if $\ce{NaOH}$ (in solid state) is added to water, it just dissociates into its constituent ions that are $\ce{Na+}$ and $\ce{OH-}$. You can add any ratios of two until you cannot add any more.

• He doesn't want to admit I am right. When I showed him what you said he just clicked the power button on my laptop. – Alek Aug 7 '16 at 18:42
• did he prove to you that it is a "compound" – jaspreet Aug 7 '16 at 18:43
• Another take could be this: Assuming it is a chemical compound, it must mixture possess the characteristics a chemical compound must have, then show that that mixture of water does not have those properties, one of them being the fixed ratio thing, and if this is the case, our assumption is wrong that is mixture of water and sodium hydroxide is not a chemical compound. – jaspreet Aug 7 '16 at 18:47
• @Alek It may be futile to argue with a brick wall... – MadisonCooper Aug 7 '16 at 22:20

What exactly counts as a compound is not exactly clear cut, and probably not a really useful distinction a lot of the time. It's fair to say that a solution of NaOH in water is not a new compound, though.

If you start with pure crystals of NaOH however, adding water can create new compounds: NaOH.1H2O and NaOH.4H2O (the tetrahydrate appears to be polymorphic, so there's another can of worms there).