Sciencemadness Discussion Board

KOH reacted with paper

JibbyDee - 20-1-2012 at 04:53

I improvised a weigh boat out of a piece of paper and used it to weigh out some KOH. There was a flake or two left in the weight boat. An hour later the KOH had turned into a yellow liquid. There was no water there to begin with. Did the KOH absorb the moisture from the paper or something? If so, what caused the yellow color?

Bot0nist - 20-1-2012 at 05:21

KOH is very hygroscopic and will readily absorb enough moisture from the environment to dissolve itself. The formed KOH solution surly affected the paper. It's used as drain opener (NaOH maybe) and will break down many organics.

It's hygroscopic nature is what makes thoroughly dried KOH a great desiccant.

[Edited on 20-1-2012 by Bot0nist]

AirCowPeaCock - 20-1-2012 at 09:31

isn't their a name for that, when a substance is so hydroscopic it will form a solution from atmospheric moisture?

and I've never heard of KOH as a drain cleaner, but NaOH is definitely used as drain cleaner.

[Edited on 1-20-2012 by AirCowPeaCock]

AirCowPeaCock - 20-1-2012 at 09:34

Wait I found it, the property is called Deliquescey(?)..some alteration of Deliquescent

Bot0nist - 20-1-2012 at 12:16

NaOH is preferable for it's increase solubility. KOH retains the same caustic properties though.

AirCowPeaCock - 20-1-2012 at 13:12

according to the wiki, KOH has increased solubility..I think, let me double check

AirCowPeaCock - 20-1-2012 at 13:15

Yup (well at-least probably), according to wiki
NaOH 1110 g dm-3 (at 20 °C)
KOH 1210 g/L (25 °C)

is NaOH cheaper perhaps?

Bot0nist - 20-1-2012 at 13:32

Yup, sorry, your right.

"KOH and NaOH can be used interchangeably for a number of applications, although in industry, NaOH is preferred because of its lower cost."-wiki

Endimion17 - 20-1-2012 at 17:02

It's an intermediate product in the formation of viscose.
You can make it by reacting cellulose with any strong base (that gives something that could be called natron cellulose, if the base was NaOH), then dissolving the compound with carbon disulphide which takes quite some time.

AirCowPeaCock - 20-1-2012 at 19:33

Sounds cool, I'm thinking of compiling a polymer project for school, I guess so far I have rayon and polycarbonate, unfortunately I can't make my favorite plastic, HDPE.. but that's off topic