[chemicalLindsay]

hey does anyone know any good acid/base indicators that can be made from vegetables and any other houshold items so that i  can have an indicator for my tritration experiments that I want to carry out.

[Donaldson Tan]

Have you seen those purple-coloured cabbage in the market or supermarket?

You can extract the purple pigment by boiling it inside ethanol via a water bath. This pigment can be used as an indicator. Think you might need to calibrate it to know what colour it is to represent a particular pH range.

[chemicalLindsay]

know ethanol is a hydrocarbon and basically is alcohol isn't it.So in order to make it for boiling in a water bath (what is that?) I would probably have to distill it from beer or something like that which could be dangerous (explosive) and very hard so I am not going to do it.The question is ,are there any other safer ways to make an acid/base indicator out of fruits and vegetable etc.

[hmx9123]

You could get your parents to buy you some Everclear--it's just grain alcohol.  However, you could probably get the same effect with rubbing alcohol, which is isopropanol.  The red cabbage indicator is a pretty good one, and if you look up 'red cabbage indicator' on google, I bet you can find some pretty good writeups for it.  The university I used to teach at used to use the red cabbage indicator in the first year labs.

[jdurg]

Yeah, ethanol is just ethyl alcohol which is drinking alcohol.  Grain alcohol purchased from a liquor store is 95% pure ethanol, and it's as strong as you can get it without doing some pretty nasty distillation/chemical reactions.  Isopropanol will almost certainly work just as well with this, and you can get pure isopropanol from a drug store.  (Rubbing alcohol).

[Donaldson Tan]

You can extract the purple pigment by boiling it inside ethanol via a water bath.

I had meant warming the big tube of ethanol inside a water bath, so as to avoid direct flame.

[chemicalLindsay]

Thanks I have allready found some really good recipees on how to make it!

[mike]

In case people are interested in making it at home the cabbage can just be boiled in water, there is no need to use ethanol