red cabbage indicator experiment (1 Viewer)

[tazzyboys]

what were the color changes for acid/neutral and base

 

[appletooth]

Acid (HCl) = Pink
Neutral (H2O) = Purple
Base (NaOH) = Yellow

And originally, the indicator itself was purple.

 

[minijumbuk]

Acid - Red
Neutral - Blue
Base - Green

 

[danz90]

Acid - Red
Neutral - Blue
Base - Green

Yep, sounds right.

 

[appletooth]

:| Crap, maybe our cabbage was off. Should I be worried? Can anyone else confirm that red/blue/green were the correct colours?

 

[tegzy26]

our classes results were as follows

Acid: pink (although a few looked more red than pink)
Base: green turning yellow
Neutral: purple.

the dotpoint hsc chem book states that the colours are meant to be
acid: pink
base:green
Neutral: purple

and the macquarie hsc chem book states that "If you used purple cabbage then you may find that the purple(neutral) extract changes as more drops of dilute acid or base are added"
(results as given by macquarie hsc book)
Acidic: purple turns to pink then red
Neutral: purple
Base: purple turns to blue-green then yellow.

so maybe your cabbage wasnt off but ur water may have been slightly basic?

 

[appletooth]

Ok thanks I'm going to go with the results I have, since it's pretty similar to the macquarie book.

 

[steffiiii]

when we did it
acid=>purple
base=>green (almost emerald green)


.... another question: did you guys use water or ethanol? cause text books say to use ethanol and we used water... what did you guys use?

 

[Undermyskin]

Use can use either one. In fact, by crashing the cabbage then filtering off the juice, you can use it straight away without dissolving into any other solvents to increase the volume of your indicator.

And, for NaOH, it does turn yellow. The green or aqua colours do depend on the []s and strength of the bases you use. As far as I did, by using 1M solutions, aqua is for NH3. Besides, red for HCl, pink for CH3COOH.

 

[Darrow]

Pfft Beetroot ftw

 

[Gmook]

I do realise this post is pretty dead, but instead of creating a new one i thought id just try asking here. With the cabbage indicator, does the colour change around pH=7 then? As in even at pH=6 u can see the red and at pH=8 the green/yellow?

 

[adnan91]

Pfft Beetroot ftw

Agreed

 

[SkimDawg]

Fuck yes another prac I didn't do....... wish teachers were up to date with this shit. Thanks for informing me on this prac guys.

 

[danz90]

Fuck yes another prac I didn't do....... wish teachers were up to date with this shit. Thanks for informing me on this prac guys.

It's pretty easy... just remember that you boil cabbage to remove the organic pigment, which itself is an indicator.

In our experiment.. we found green/yellow to indicate alkaline, and bright pink/magenta to indicate acidity.