What is the net ionic equation of sodium hydroxide when it dissolves in water? What is the net ionic equation of sodium hydroxide when it dissolves in water?  

For the net ionic equation I got 
$$\ce{NaOH(s) + H2O(l) -&gt; NaH+(aq) + OH- (aq) + H2O(l)}$$
but it was wrong. 
Then I tried:
$$\ce{NaOH(aq) -&gt; Na+(aq) + OH- (aq)}$$
and it was wrong as well. 
Can someone please explain?
When you write down the net ionic equation, you have to consider that the educt and the products are in different phases, a solid and a liquid phase. Undissolved $\ce{NaOH}$ is a solid, denoted by the index $\ce{(s)}$, while the dissolved $\ce{Na+}$ and $\ce{OH-}$ ions are solvated in the aqueous phase (index $\ce{(aq)}$ in the equation):

$$\ce{NaOH(s) ~-&gt;~ Na+(aq) + OH^{-}(aq)}$$