Topic: Indicator doesn work? (Read 4588 times)

NecromancerLV6 · « **on:** April 23, 2006, 10:17:11 AM »

I have some copper (II) sulphate and bromothymol blue and I added in together, how come it didn't work?

Borek · « **Reply #1 on:** April 23, 2006, 10:41:22 AM »

What effect have you expected?

NecromancerLV6 · « **Reply #2 on:** April 23, 2006, 10:54:51 AM »

Um.....yellow? isn't that's what the indicator is suppose to show?

Borek · « **Reply #3 on:** April 23, 2006, 11:34:12 AM »

NecromancerLV6 · « **Reply #4 on:** April 23, 2006, 11:37:03 AM »

copper sulphate is slightly acidic, then why shouldn't it show on the indicator? (info got from notes in school)

Borek · « **Reply #5 on:** April 23, 2006, 11:47:16 AM »

Slightly - so it will all depend on the concentrations. I can't check details right now as I am leaving in few minutes, but my intuition is - copper sulphate changes pH, but change is masked. Cu²⁺ makes the solution bluish, thus making yellow more difficult to spot.

Also - have you used solid CuSO₄, or lab solution? Lab solutions are often acidified.

NecromancerLV6 · « **Reply #6 on:** April 23, 2006, 11:51:38 AM »

I used solution. Thanks. I think I figured out the problem now.

Topic: Indicator doesn work? (Read 4588 times)

NecromancerLV6

Indicator doesn work?

Borek

Re: Indicator doesn work?

NecromancerLV6

Re: Indicator doesn work?

Borek

Re: Indicator doesn work?

NecromancerLV6

Re: Indicator doesn work?

Borek

Re: Indicator doesn work?

NecromancerLV6

Re: Indicator doesn work?

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