[crazybombmaker123]

Na + H2O --> H2 + NaOH. why there is a lot of white fumes generated? hydrogen gas is colorless. NaOH is in solution in water.

[Arkcon]

Any exothermic reaction can generate a mist of the aqueous phase, or steam is a possibility.  Note: The released hydrogen may ignite from the heat.  Neither hydrogen nor aqueous NaOH looks like a blue burning hydrogen flame, except you know, burning hydrogen does.  Also, neither looks like an oxygen-hydrogen explosion, but you can still get to see one if you're nit careful.

[crazybombmaker123]

yeah but can NaOH be gas then? im talking about throwing a lump or sodium in water, it explodes and flies into air and you get alot of white fumes.
Na can burn, or ya know, react with oxygen once its hot and already going, so Na + O2 --> Na2O ? i want to know what the fumes are.

[Borek]

Fumes you see are not pure NaOH, but aerosol of tiny droplets with (most likely) high NaOH concentration.