Hey there,

 

Under what conditions can 2Na + 4H2O bond as 2NaHO + 2H2O + O2?

none as that equation requires 2 oxygens to appear out of nowhere and 2 hydrogens to disappear.

 

the proper equation is Na + H₂O --> NaOH + 0.5H₂

It may just be me, but I think if you are going to talk about a "proper equation" you shouldn't have fractions in th coefficients.

why not? you can get 0.5 mol of hydrogen.

 

if you react 1 mol of sodium with 1 mol of water you get 1 mole of sodium hydroxide and a half mol of hydrogen.

 

it is a perfectly valid chemical equation.

Yeah fasttoyotapu , that is the reaction!

[ce]2Na + 2H2O -> 2NaOH + H2[/ce]

 

All the elements of I and II group (with few exceptions) when reacting with water give the the base (in this case NaOH) and hydrogen is released.

 

In the reaction above, there also is released a good deal of energy (so the reaction is exothermic), but unless localized that energy isn't enough to set hydrogen on fire.

 

Cheers,

Shade

And about the conditions... it will always react. So, you need "wet conditions" since you'll need water. But you had already put that in the original question.

 

Other conditions (temperature, pressure) are quite irrelevant.

 

If I really search for that one condition where it will not react: a perfect vacuum. The water will all evaporate, and without it, the reaction does not proceed.

 

The reaction you entered is indeed slightly wrong. Count the H, O and Na on both sides of the arrow. These must always be the same. (This is called "stoichiometry"). Wikipedia it to get a good explanation.