phosphoric acid and methyl violet

[RosalieL]

Is rustbuster from bunnings a suitable substitute for phosphoric acid? The description online just says it is phosphoric acid but I can't see if there are other additives.

Also, is there a substitute for methyl violet?

The prac is to show the effect of temperature on equilibrium yields and these are the two chemicals involved and I have neither.

I'm also open to alternatives to this prac using things I should already have!

[mtg]

There is 2 more parts to this prac. per student: 5 x 10-4M Fe(SCN)2+ solutions. and 2 x stoppered test tubes containing an NO2/N2O4 mixture. It's in my old Heinemann Chemistry TWO teachers resource book. We aren't running yr 12 chem atm so I don't have the current prac book. I remember it worked well. I did use methyl violet and phosphoric acid. You can google the SDS for Bunnings rustbuster which should give you % of acid. Crystal violet, (Gentian violet) might work I think they are the same thing. Look up the recipe as it is often used as a stain and you want a different make up.

[bigmack]

Doesn't look good

Rustbuster.png

RANEX RUST BUSTER.pdf

[RosalieL]

I've just ordered them from westlab and hopefully they arrive in time for the lesson...

[Marama T]

Good luck!

[bigmack]

and 2 x stoppered test tubes containing an NO2/N2O4 mixture.

Is that the one where the tubes are placed in different temperatures , Fridge , Freezer and Room temp and the gas goes from Brown to almost clear ?

If so be careful .

At my old school we were lucky enough to have had sealed glass tubes of NO2
I remember doing a casual week at another School and having to make sealed Test tubes of it . Made it in Fume hood by dissolving pieces of Copper in Nitric Acid .
Collecting the gas is dangerous . It does nasty stuff to human flesh . I remember not having a stopper so stuck my thumb over end of Test tube . Had a nasty brown flesh wound in thumb for about Three weeks . Hate to imagine breathing that gas …. It’s nasty .

Be careful …. Think through the procedure if you need to make that stuff so you are prepared.

[Merilyn1]

Also be concerned if the glass tubing were to break.
My HT would not allow it at all. I was very thankful of that!

[mtg]

To get the NO2 I use a quick fit set up and put the tubing up through a beehive in a trough of water, I have the test tubes ready and wear full PPE and do it in the fume hood. Sometimes I used a gas jar and for another prac, gas syringes.