i'm suppose to write an equation with Al(s)+NaOH

 

i can't figure out why i've balanced this wrong

 

Al(s) + Na+(aq) + 2OH- + 2H20---> Na+ +Al(OH4)- +H2(g)

 

and why its suppose to be

 

2Al(s) +2Na+ +2OH-(aq) +6H20 ---> 2Na+ + 2[Al(OH)4]-(aq) +3H2(g)

 

sorry, thanx!