Synthesis of Sodium Hydroxide

[rthmjohn]

Actually, aluminum is one of the few metals that will react with NaOH.

 

True... what i think he meant was aluminum + water. The aluminum oxide passivation layer on the aluminum metal is what reacts with the NaOH. The pure aluminum then reduces the water and is oxidized to (Al(OH)4)-

[woelen]

Indeed, this evening I'll put this question in front of our final jury, being Nature itself

Nature has decided.....

 

I put a large spatula full of sodium bicarbonate in a test tube and added approximately 5 ml of distilled water.

Next, I started heating the test tube. Well before the water starts boiling, the solution starts to bubble quite a lot. Many small bubbles escape from the liquid. This must be CO2. I continued heating but not boiling for several minutes, until bubbling ceased. After bubbling ceased, I boiled the solution for several minutes. It might be that more bubbles of CO2 were released, but of course, one cannot really see, because of the boiling of the water.

 

In total, I have been heating for more than 10 minutes, and quite some water had evaporated.

 

Next, the liquid was allowed to cool down. I measured the pH of the liquid, using a multi-color pH indicator. Using this indicator, I measured a pH around 10. So, the liquid definitely has become alkaline, but not nearly as much as a similar solution of NaOH. When a spatula full of NaOH is dissolved in 5 ml of water, then the pH will be around 14. Looking up the Kb value of Na2CO3, a pH around 10 can be explained very well. So, indeed, boiling a solution of NaHCO3 does not give NaOH, but Na2CO3.

 

As I explained before this experiment, it can be understood simply from the fact that OH(-) and HCO3(-) react with each other giving CO3(2-) and H2O. Even at boiling temperatures, the CO2 is bound sufficiently strongly by the solution in order to prevent escape into the air.

 

I think this issue has settled now.

[BenSon]

Ok, I still reserve the right to try it myself before I fully commit but I must admit right now its not looking good

 

`Scott

[woelen]

Ok' date=' I still reserve the right to try it myself before I fully commit but I must admit right now its not looking good

 

`Scott[/quote']

You not only have the right to do so, even stronger, I invite you to do so .

[xeluc]

Ok guys... FYI.. I just bought some NaOH ... HAHA.. Ok Round 2..... ding ding ding...

[woelen]

Ok guys... FYI.. I just bought some NaOH ... HAHA.. Ok Round 2..... ding ding ding...

You did a wise thing, my boy!