Sodium hydroxide - without water - 50%solution

Question

Hello,

I need to add an input of pure sodium hydroxide. I found an option for sodium hydroxide with a confusing name " sodium hydroxide, without water, in 50% solution state". Is it just sodium hydroxide or does it have water? To my knowledge, if the NaOH is in solution state, then it is with water. In the information of the flow I found that it is modelled as a pure substance; if so, why bothering naming it "in 50% solution state"?

I appreciate your thoughts on this. Thank you for your help

Answer 1

I had the same issue that it is written "without water" and "50% solution state" at the same time in ecoinvent. This is also the case e.g. for acids and intuitively you would not know if it is modeled without water or in a solution state with water. In the product informations of the database overview file from ecoinvent and in ecoquery you can find that the solvent needs to be added (see below). So I guess that the XX% solution state is only referring to the most used solution or to the original model of the data in some cases, but not to the current state in the database, which is without a solvent (theoretically). In the openLCA implementation for the next ecoinvent version we will have the information directly in the description tab. 

'sodium hydroxide, without water, in 50% solution state' is an inorganic substance with a CAS no. : 001310-73-2. It is called 'sodium;hydroxide' under IUPAC naming and its molecular formula is: HNaO. It is solid under normal conditions of temperature and pressure , it appears as a white powdery solid, which are soluble in glycerol, alcohols and water. It is modelled as a pure substance. Industrially, this product is mostly used in 50% solution state. Modelling this substance in a solution requires the user to add the solvent of their choice in their models. On a consumer level, is used in the following products: laboratory chemicals. There is no publicly available information about the consumption of this substance on industrial sites.