Question

The reaction of sodium metal with water is the following.
2Na+2H2O---->2NaOH+H2
what type of a reaction is this (i.e. double replacement, single replacement, neutralization, etc.) Thanks for answering.

Answer 1

It is single reaction. You can get more definitions and examples here.
http://misterguch.brinkster.net/6typesofchemicalrxn.html

Answer 2

So since the hydrogen is less active as compared to sodium, sodium will replace the hydrogen. But how do you know that the reaction will produce sodium hydroxide, like why the hydroxide.

Answer 3

Never mind. The hydroxide is kind of like the anion of the of water (I know it is not technically correct, but I like to think of it that way because it helps me remember) so the sodium will replace one H, just like it would replace any less active metal.