Sciencemadness Discussion Board

A very unexpected reaction..(or lack of)

gardul - 18-10-2014 at 13:16

Good afternoon everyone,

I have been reading these forums for awhile now but never really needed to post anything until now.

When the final solution was made I did a flame test only to find out that the 91% isopropyl Alcohol would not ignite at all. Below is every step I took.

The first step I was making Ammonium Chloride. I'm sure I dont have to explain this.

The second was Boric acid from Sodium tetraborate. ( i will explain how this is made if someone asks)

when the two products where dry the powders were mixed. Each containing 1g. 1ml of isopropyl Alcohol and it ignites with an orange flame. I would assume this is due to the Sodium tetraborate that may have been left over.

Then I mixed the following in a flask.

5g of ammonium chloride
5g of boric acid
50ml of isopropyl Alcohol
50ml of hydrogen peroxide

Everything was mixed until the powder mix was fully dissolved. When poured into what I use for liquid flame tests... it wouldn't ignite. so I brought it over to the burner, and heated it up to 75C and it produced a foam like subsistence and a gas. I trapped the gas and it seems to be hydrogen. I took a PH reading and it stated the PH level was 5 at the time. What I am curious about is if anyone has an idea on why this wouldn't ignite. thank you for your time and your Ideas.

subsecret - 18-10-2014 at 13:46

What was the purpose of the reaction, and what was the concentration of the H2O2?

gardul - 18-10-2014 at 14:09

H2o2 was 30%. the even mixture is still flammable. even H2O2 at 3% mixed evenly with 91% isopropyl Alcohol is still some what flammable as long as a flame is held to the mixture.

If you don't believe me, do this yourself. take 2 ml 3% H2O2 and mix 2 ml of 91% isopropyl Alcohol. Light a splint. it will still ignite. it takes fractions of a second longer but it still ignites.

The purpose of this experiment was to create "liquid flux" for another project.

Metacelsus - 18-10-2014 at 14:18

How do you know the gas was hydrogen? Oxygen seems more likely, or even possibly nitrogen (from oxidation of ammonia?).

gardul - 18-10-2014 at 14:28

I caught some of the gas in a test tube. opened it up and placed a lit split to it. it popped like most basic hydrogen experiments do. Granted, I do not have much experience with nitrogen gas so i'm not extremely familiar on how that would react to to an open flame. I am pretty sure it wasn't oxygen.

DrMario - 18-10-2014 at 14:29

Like Cheddite Cheese, I also doubt the gas is hydrogen. Luckily, hydrogen is trivial to determine.

hyfalcon - 18-10-2014 at 14:47

Carbon monoxide is flammable.

gardul - 18-10-2014 at 15:35

What I am thinking it is now is probability a mixture of Oxygen and traces of ethanol gas. It reacted a little differently. this time and the many test afterward. When the flame is placed into the test tube it gets slightly bigger and then has a pop. a glowing splint will ignite. If I remember correctly from chemistry class back in middle school this is a sign of oxygen. Any one disagree with this thought? I would assume that the ethanol gas is what is producing the popping sound

DraconicAcid - 18-10-2014 at 15:39

Quote: Originally posted by gardul  
I caught some of the gas in a test tube. opened it up and placed a lit split to it. it popped like most basic hydrogen experiments do. Granted, I do not have much experience with nitrogen gas so i'm not extremely familiar on how that would react to to an open flame. I am pretty sure it wasn't oxygen.


Oxygen mixed with isopropanol vapours would probably pop nicely.

gardul - 18-10-2014 at 15:51

Quote: Originally posted by DraconicAcid  
Quote: Originally posted by gardul  
I caught some of the gas in a test tube. opened it up and placed a lit split to it. it popped like most basic hydrogen experiments do. Granted, I do not have much experience with nitrogen gas so i'm not extremely familiar on how that would react to to an open flame. I am pretty sure it wasn't oxygen.


Oxygen mixed with isopropanol vapours would probably pop nicely.


Yea I just figured that part out actually. What still boggles my mind is why a flame wont ignite the liquid.

hyfalcon - 18-10-2014 at 17:20

Something to do with vapor pressure probably plus containment.

DrMario - 18-10-2014 at 17:54

Quote: Originally posted by gardul  
What I am thinking it is now is probability a mixture of Oxygen and traces of ethanol gas. It reacted a little differently. this time and the many test afterward. When the flame is placed into the test tube it gets slightly bigger and then has a pop. a glowing splint will ignite. If I remember correctly from chemistry class back in middle school this is a sign of oxygen. Any one disagree with this thought? I would assume that the ethanol gas is what is producing the popping sound

I agree with your analysis. It did occur to me that you have produced oxygen, but your high self-confidence that it's hydrogen made me hesitant. But trace amounts of ethanol would indeed explain the pop.

gardul - 19-10-2014 at 07:44

I do apologize if i came off as being arrogant. I am not a very good story teller. I'm sure that there where better ways of stated what I did. Plus only doing some thing once was foolish on my part. Again I am sorry if I came off strong. I am here to learn and listen.

Dan Vizine - 19-10-2014 at 09:59

Don't sweat it, gardul. You didn't offend anyone.

Forum communication is limited in conveying subtleties, the forum members consist of a very mixed bag, everything from beginners to top flight scientists and as much as we all try to restrain it, everybody has a certain degree of ego that slips past the filters.

subsecret - 20-10-2014 at 16:09

I second that, Dan.

If you think it's isopropanol, you could try to pass the vapors into a chilled test tube, which would condense the alcohol.