1
$\begingroup$

I am not expert in chemistry.I learned about combustion in reaction when added glycerine to potassium permagnet.I tried it at home, I took potassium permagnet in test tube and when I added glycerine to it test tube just CRACKED as combustion started.I want to know why, because it lab we some time directly heat test tube, it does not cracked so why this time..

I am not sure I should continue on sulfuric acid and potassium parmagnet test in a TEST TUBE after seeing this affect...

Any Suggestion..

$\endgroup$
3
$\begingroup$

I am not sure I should continue on sulfuric acid and potassium parmagnet test in a TEST TUBE after seeing this affect...

In case of doubt you should not. Anyway, I recommend to avoid doing it with any significant amount. It may and will spread around and even if not it produces manganese (IV) oxide smoke that settles down nearby and is quite hard to wash out.

I want to know why, because it lab we some time directly heat test tube, it does not cracked so why this time..

Potassium permanganate is a strong oxidizer, glycerol is a reducer. Mixed together they quickly start to react. The exact nature of the products is debatable, but the mixture self-ignites if warm. The thermal shock is enough to crack glass. This is a common weakness of glass and ceramics.

Furthermore, in case of bad luck it may produce enough gases to spread the mix around. Consequently, safety precautions must be always employed (incombustible table, safety goggles etc). A movie how it may go http://www.youtube.com/watch?v=6F4cuQkKt2U . The reaction has some quirks, specifically if the glycerol is cold, it may not start immediately, so a rather well mixing is achievable. Now, once it warms up to room temperature, it suddenly bursts in flame, potentially delivering itself to nearby surfaces, including your face.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.