Purity of lye

[Liorasol]

This may be a silly question

“Composition/ information ingredients:
Substances
Synonyms: Caustic Soda
Formula: NaOH
Molecular Weight: 40.00g/mol
Chemical Name %
Sodium Hydroxide 100”

Does this mean my sodium hydroxide has a purity of 100%?? I’ve heard that’s very seldom

 

[Midnight_Sun]

I am sure someone who is much smarter than me will correct me if I’m wrong here.

The reason lye purity is never 100% is not necessarily that other things are added to the lye. Rather it is that even if you start with 100% pure lye, the sodium hydroxide will react with the carbon dioxide and moisture in the air. This creates uses up a tiny bit of the lye and creates new compounds in the container of lye. This reduces the purity of the lye and it is no longer 100% sodium hydroxide.

I would interpret this label as the company saying the container they sold you was only filled with sodium hydroxide with no additional known components. Ie: it started as 100% lye.

 

[Liorasol]

I am sure someone who is much smarter than me will correct me if I’m wrong here.

The reason lye purity is never 100% is not necessarily that other things are added to the lye. Rather it is that even if you start with 100% pure lye, the sodium hydroxide will react with the carbon dioxide and moisture in the air. This creates uses up a tiny bit of the lye and creates new compounds in the container of lye. This reduces the purity of the lye and it is no longer 100% sodium hydroxide.

I would interpret this label as the company saying the container they sold you was only filled with sodium hydroxide with no additional known components. Ie: it started as 100% lye.

Thank you!

 

[DeeAnna]

That 100% means it's all NaOH -- there are no other ingredients intentionally added to the product.

You will never find NaOH that has a purity of 100%. It might be 99% or even somewhat higher. But never 100%.