# In which conditions Na_2O reacts with H_2O to form NaOH?

$N {a}_{2} O + {H}_{2} O \left(l\right) \rightarrow 2 N a O H \left(a q\right) + \Delta$
Sodium oxide is thus the $\text{base anhydride}$ of sodium hydroxide. When you open a tin, the white powder is usually contained in a plastic bag, so that it does not undergo reaction with moist air.