[AhBeng]

Can someone please confirm what is "fused" NaOH? And how is it different from say, concentrated NaOH? Couldn't find anything from google or wiki on it.

Thanks in advance!

[Mitch]

Haven't heard of it specifically. But I would suspect fused NaOH means Naoh in the solid state, while concentrated NaOH is definitely referring to NaOH dissolved in water. 

[AhBeng]

Yes, that certainly makes sense. And based on your lead, I did some further checking and indeed :

The electrolyte for the electrolytic cell consists of molten (fused) sodium carbonate...

and

The heat of fusion is the heat in calories required to convert 1 g of a material from the solid to the liquid state at the melting temperature...

This explains why fused (ie. molten, not aqueous) NaOH is even more reactive than concentrated aqueous NaOH, which explains why fused NaOH can react readily with silicon dioxide (an acidic oxide yet inert with aqueous alkalis, even concentrated NaOH). And this was the original discussion which brought me to ponder what "fused" meant.

Thanks again for your help, Administrator Mitch! 

[limpet chicken]

Careful with it too in the molten state, it burns through jeans, leather, arms like nobodys business.

Unlike acids you might not feel it until the damage has already been done.

[AhBeng]

Thanks for the heads up... I can imagine one's entire life (and also one's potential offspring, no more... dissolved away by molten NaOH... OUCH!!!) ruined in a moment of carelessness...